05 piston 2-3 fuel metering system

RECIPROCATING ENGINE

FUEL METERINGSYSTEM

1PISTON 2-3LOW SD/JUN 2010

INTRODUCTIONINTRODUCTION

• EXPLAIN THE PROPERTIES OF EXPLAIN THE PROPERTIES OF RECIPROCATING ENGINE FUELS.RECIPROCATING ENGINE FUELS.

• EXPLAIN THE OPERATION AND EXPLAIN THE OPERATION AND MAINTENANCE OF THE RECIPROCATING MAINTENANCE OF THE RECIPROCATING ENGINE FUEL METERING SYSTEM.ENGINE FUEL METERING SYSTEM.

• TO FAMILIAR WITH VARIOUS TYPES OF TO FAMILIAR WITH VARIOUS TYPES OF FUEL METERING DEVICES USED ON FUEL METERING DEVICES USED ON AIRCRAFT RECIPROCATING ENGINE.AIRCRAFT RECIPROCATING ENGINE.

RECIP. ENGINE FUELS PROPERTIESRECIP. ENGINE FUELS PROPERTIES

MOST CRITICAL CHARACTERISTIC IS MOST CRITICAL CHARACTERISTIC IS VOLATILITYVOLATILITY

IS THE ABILITY TO CHANGE FROM LIQUID IS THE ABILITY TO CHANGE FROM LIQUID TO VAPOUR, EXPRESS IN REID VAPOUR TO VAPOUR, EXPRESS IN REID VAPOUR PRESSUREPRESSURE

REPRESENTS AIR PRESSURE ABOVE A REPRESENTS AIR PRESSURE ABOVE A LIQUID REQUIRED TO PREVENT VAPOURS LIQUID REQUIRED TO PREVENT VAPOURS FROM ESCAPING FROM LIQUID AT A GIVEN FROM ESCAPING FROM LIQUID AT A GIVEN TEMPERATURETEMPERATURE

EG. 100LL IS APPROX. SEVEN POUNDS PER EG. 100LL IS APPROX. SEVEN POUNDS PER SQUARE INCH AT 100°FSQUARE INCH AT 100°F

PROPERTIES PROPERTIES CONTCONT..

FUEL MUST VAPOURISED READILY TO BURN FUEL MUST VAPOURISED READILY TO BURN EVENLYEVENLY

POOR VAPOURISING WILL CAUSE TOO SLOW TO POOR VAPOURISING WILL CAUSE TOO SLOW TO ATOMISED AND CAUSE HARD STARTING AND ATOMISED AND CAUSE HARD STARTING AND ROUGH RUNNINGROUGH RUNNING

BUT TOO READILY WILL CAUSE VAPOUR LOCK BUT TOO READILY WILL CAUSE VAPOUR LOCK AND CARBURETOR ICEAND CARBURETOR ICE

FORMULATED TO BURN SMOOTHLY WITHOUT FORMULATED TO BURN SMOOTHLY WITHOUT DETONATION OR KNOCKINGDETONATION OR KNOCKING

GRADE 80 MEANS 80% OF ISO-OCTANE TO 20% GRADE 80 MEANS 80% OF ISO-OCTANE TO 20% NORMAL NEPTANENORMAL NEPTANE

TWO NUMBER 100/130 MEANS LEAN/RICH MIXTURETWO NUMBER 100/130 MEANS LEAN/RICH MIXTURE

PROPERTIES PROPERTIES CONTCONT..

TO AVOID CONFUSSION AND ERRORS, NOW TO AVOID CONFUSSION AND ERRORS, NOW DESIGNATE BY LEAN MIXTURE NUMBERS ONLY DESIGNATE BY LEAN MIXTURE NUMBERS ONLY EG. AVGAS 80EG. AVGAS 80

100LL PERFORMS THE SAME AS 100/130 BUT 100LL PERFORMS THE SAME AS 100/130 BUT WITH LOW LEAD CONTENTWITH LOW LEAD CONTENT

TETRAETHYL LEAD ADDED TO PREVENT TETRAETHYL LEAD ADDED TO PREVENT DETONATION BUT CAUSE FORMING OF DETONATION BUT CAUSE FORMING OF CORROSIVE COMPONENTS IN COMBUSTION CORROSIVE COMPONENTS IN COMBUSTION CHAMBERCHAMBER

ETHYLENE BROMIDES ARE ADDED TO ACTIVELY ETHYLENE BROMIDES ARE ADDED TO ACTIVELY COMBINE WITH LEAD OXIDES AND DISCHARGE COMBINE WITH LEAD OXIDES AND DISCHARGE FROM CYLINDER DURING OPERATIONFROM CYLINDER DURING OPERATION

PROPERTIES PROPERTIES CONT.CONT.

AVGAS ARE VISUALLY IDENTIFIED BY COLOUR-AVGAS ARE VISUALLY IDENTIFIED BY COLOUR-CODEDCODED– 80 – RED80 – RED

– 100 – GREEN100 – GREEN

– 100LL – BLUE100LL – BLUE

MARKING & CODING ARE ADOPTED AT AIRPORT MARKING & CODING ARE ADOPTED AT AIRPORT FUEL HANDLING FACILITIES AND EQUIPMENTSFUEL HANDLING FACILITIES AND EQUIPMENTS

BY NAME WITH WHITE LETTER ON A RED BY NAME WITH WHITE LETTER ON A RED BACKGROUNDBACKGROUND

COLOUR CODED MARKING ON VALVE, LOADING COLOUR CODED MARKING ON VALVE, LOADING AND UNLOADING CONNECTION, SWITCHES AND AND UNLOADING CONNECTION, SWITCHES AND CONTROL EQUIPMENTCONTROL EQUIPMENT

COLOURS AND TYPES OF COLOURS AND TYPES OF MARKING USE ON AVGASMARKING USE ON AVGAS

PROPERTIES PROPERTIES CONT.CONT.

FUEL TRUCKS AND HYDRANTS CARTS FUEL TRUCKS AND HYDRANTS CARTS MARKED WITH LARGE DECALS ON EACH MARKED WITH LARGE DECALS ON EACH SIDE OF THE TANK OR BODY AND SMALL SIDE OF THE TANK OR BODY AND SMALL DECAL ON DASHBOARD OF SAME COLOUR DECAL ON DASHBOARD OF SAME COLOUR CODECODE

IN FACT, ALL PARTS OF FUELLING IN FACT, ALL PARTS OF FUELLING FACILITY AND EQUIPMENTS ARE COLOUR FACILITY AND EQUIPMENTS ARE COLOUR CODED AND MARK WITH THE SAME CODED AND MARK WITH THE SAME MARKINGMARKING

FUEL SYSTEM REQUIREMENTSFUEL SYSTEM REQUIREMENTS

ALL FUEL SYSTEM MUST:ALL FUEL SYSTEM MUST:– CONSTRUCTED AND ARRANGE TO GIVE CONSTRUCTED AND ARRANGE TO GIVE

POSITIVE FUEL FLOW IN ALL CONDITIONPOSITIVE FUEL FLOW IN ALL CONDITION

– EACH TANK HAVE ITS OWN PUMP AND EACH TANK HAVE ITS OWN PUMP AND DESIGNED SO THAT NO AIR TO BE DRAWN INTO DESIGNED SO THAT NO AIR TO BE DRAWN INTO LINESLINES

– SHUT OFF VALVE FOR EACH ENGINE AND NOT SHUT OFF VALVE FOR EACH ENGINE AND NOT LOCATED ON ENGINE SIDE OF FIREWALL AND LOCATED ON ENGINE SIDE OF FIREWALL AND OF INDEPENDENT TO EACH ENGINEOF INDEPENDENT TO EACH ENGINE

– TANKS HAVE TWO VENTS TO PREVENT TANKS HAVE TWO VENTS TO PREVENT LIKELYHOOD OF BOTH VENTS PLUGGEDLIKELYHOOD OF BOTH VENTS PLUGGED

– DESIGN TO PREVENT THE IGNITION OF FUEL DESIGN TO PREVENT THE IGNITION OF FUEL VAPOUR BY LIGHTNING……….VAPOUR BY LIGHTNING……….

RECIP. ENGINE FUEL SYSTEMSRECIP. ENGINE FUEL SYSTEMS MUST SUPPLY PROPER AMOUNT OF FUEL TO MUST SUPPLY PROPER AMOUNT OF FUEL TO

ENGINE AT RIGHT PRESSURE DURING ALL ENGINE AT RIGHT PRESSURE DURING ALL OPERATING CONDITIONOPERATING CONDITION

BASIC COMPONENTS ARE:BASIC COMPONENTS ARE:FUEL TANK/SFUEL TANK/SLINESLINESVALVESVALVESFILTERING DEVICESFILTERING DEVICESQUANTITY GAUGES, ANDQUANTITY GAUGES, ANDA PRIMERA PRIMER

TWO BASIC SYSTEM:TWO BASIC SYSTEM:GRAVITY-FEED SYSTEM, ANDGRAVITY-FEED SYSTEM, ANDPRESSURE-FEED SYSTEMPRESSURE-FEED SYSTEM

GRAVITY-FEED SYSTEMSGRAVITY-FEED SYSTEMS

SIMPLEST FORM USE ON HIGH-WING SIMPLEST FORM USE ON HIGH-WING SINGLE ENGINE A/CSINGLE ENGINE A/C

NORMALLY HAVE:NORMALLY HAVE:– TWO FUEL TANKSTWO FUEL TANKS– A FUEL SELECTOR VALVEA FUEL SELECTOR VALVE

– A FUEL STRAINERA FUEL STRAINER

– A PRIMER, AND A PRIMER, AND

– A CARBURETORA CARBURETOR

TYPICAL GRAVITY-FEED TYPICAL GRAVITY-FEED FUEL SYSTEMFUEL SYSTEM

PRESSURE-FEED SYSTEMSPRESSURE-FEED SYSTEMS

USE ON LOW WING A/C WHERE FUEL USE ON LOW WING A/C WHERE FUEL METERING DEVICES IS ABOVE TANKSMETERING DEVICES IS ABOVE TANKS

FUEL PUMP IS USED TO PRESSURE-FEED FUEL PUMP IS USED TO PRESSURE-FEED FUEL TO FUEL METERING DEVICESFUEL TO FUEL METERING DEVICES

HIGH-WING A/C WITH FUEL-INJECTION OR HIGH-WING A/C WITH FUEL-INJECTION OR PRESSURE CARBURETOR ALSO USE THIS PRESSURE CARBURETOR ALSO USE THIS SYSTEMSSYSTEMS

A BACK-UP OR AUXILIARY PUMP IS A BACK-UP OR AUXILIARY PUMP IS INSTALLED IN CASE ENGINE-DRIVEN PUMP INSTALLED IN CASE ENGINE-DRIVEN PUMP FAILFAIL

TYPICAL PRESSURE-FEED TYPICAL PRESSURE-FEED FUEL SYSTEMSFUEL SYSTEMS

FUEL SYSTEM COMPONENTSFUEL SYSTEM COMPONENTS

BESIDE STD. COMPONENTS SUCH AS:BESIDE STD. COMPONENTS SUCH AS:– MULTIPLES FUEL TANKSMULTIPLES FUEL TANKS– LINESLINES

– FILTERING DEVICESFILTERING DEVICES

– PUMPSPUMPS

– GAUGESGAUGES– PRIMING SYSTEMPRIMING SYSTEM

SOME SYSTEMS ALSO HAVE:SOME SYSTEMS ALSO HAVE:– CENTRAL REFUELLING PROVISIONCENTRAL REFUELLING PROVISION

– FUEL DUMP VALVESFUEL DUMP VALVES– MEANS OF FUEL TRANSFERRINGMEANS OF FUEL TRANSFERRING

FUEL TANKSFUEL TANKSFUEL TANKS WERE CONSTRUCTED TO TYPE AND FUEL TANKS WERE CONSTRUCTED TO TYPE AND REQUIREMENT OF EACH AIRCRAFT TYPEREQUIREMENT OF EACH AIRCRAFT TYPEEARLY TANK ARE WELDED OR RIVETED TYPE IN A EARLY TANK ARE WELDED OR RIVETED TYPE IN A WING OR FUSELAGE CAVITYWING OR FUSELAGE CAVITYNEW MATERIAL SUCH AS ALUMINIUM ALLOYS NEW MATERIAL SUCH AS ALUMINIUM ALLOYS AND COMPOSITE MATERIAL ARE USEDAND COMPOSITE MATERIAL ARE USEDNEW TANK MAY BE INTERGRAL TANK FORM NEW TANK MAY BE INTERGRAL TANK FORM WITHIN THE A/C WINGWITHIN THE A/C WINGCONTAMINANTS SUCH AS GASKET, SEALANT & CONTAMINANTS SUCH AS GASKET, SEALANT & WATER MAY AFFECT THE OPERATION OF FUEL WATER MAY AFFECT THE OPERATION OF FUEL TANKTANKSO TANK ARE DESIGN TO HELP ALLEVIATE FUEL SO TANK ARE DESIGN TO HELP ALLEVIATE FUEL SYSTEM CONTAMINATION BY HAVING SUMP AND SYSTEM CONTAMINATION BY HAVING SUMP AND DRAIN INSTALLED AT THE LOWEST POINTDRAIN INSTALLED AT THE LOWEST POINT

FUEL TANKSFUEL TANKS CONT. CONT.

TANKS ARE ALSO DESIGN TO HAVE EXPANSION TANKS ARE ALSO DESIGN TO HAVE EXPANSION SPACE AND VENTING, FOR FUEL EXPANSION IN SPACE AND VENTING, FOR FUEL EXPANSION IN WARM TEMPERATURE AND VENTING PREVENT TANK WARM TEMPERATURE AND VENTING PREVENT TANK PRESSURISATION PRESSURISATION

FUEL FROM METERING SYSTEM WILL BE RETURN TO FUEL FROM METERING SYSTEM WILL BE RETURN TO THE TANK THAT SHALL BE USE 1THE TANK THAT SHALL BE USE 1STST , SO KNOWS THE , SO KNOWS THE SYSTEM WHEN OPERATING ENGINESYSTEM WHEN OPERATING ENGINE

SCUPPER AND DRAIN ARE SOMETIME INSTALLED SCUPPER AND DRAIN ARE SOMETIME INSTALLED NEAR FILLER NECK OF TANK TO COLLECTS FUEL NEAR FILLER NECK OF TANK TO COLLECTS FUEL OVERFLOWS AND WATER, THEN DRAIN OVERBOARDOVERFLOWS AND WATER, THEN DRAIN OVERBOARD

ENSURE THIS DRAIN ARE NOT BLOCK TO PREVENT ENSURE THIS DRAIN ARE NOT BLOCK TO PREVENT WATER AND CONTAMINANTS ENTERING TANK WHEN WATER AND CONTAMINANTS ENTERING TANK WHEN CAP IS REMOVEDCAP IS REMOVED

LINES & FITTINGSLINES & FITTINGSHEAT, VIBRATION AND CORROSIVE ELEMENTS HEAT, VIBRATION AND CORROSIVE ELEMENTS REQUIRE SPECIAL ATTENTION ESPECIALLY AT REQUIRE SPECIAL ATTENTION ESPECIALLY AT THE ENGINE COMPARTMENTTHE ENGINE COMPARTMENT

FAILURE OF LINES WILL AFFECTS ENGINE FAILURE OF LINES WILL AFFECTS ENGINE OPERATION AND MAY CAUSE IN-FLIGHT FIRE OR OPERATION AND MAY CAUSE IN-FLIGHT FIRE OR EXPLOSIONEXPLOSION

MODERN A/C LINES ARE NORMALLY OF MODERN A/C LINES ARE NORMALLY OF NEOPRENE (TEFLON) MATERIAL OF VARIOUS SIZE NEOPRENE (TEFLON) MATERIAL OF VARIOUS SIZE TO MEET REQUIREMENTTO MEET REQUIREMENT

FIRE SLEEVE, A SILICON COATED FIBREGLASS TO FIRE SLEEVE, A SILICON COATED FIBREGLASS TO INCREASE FIRE RESISTANT AND HELP PREVENT INCREASE FIRE RESISTANT AND HELP PREVENT DETERIORATIONDETERIORATION

ADDITIONALLY STAINLESS STEEL HEAT SHIELD ADDITIONALLY STAINLESS STEEL HEAT SHIELD ARE ALSO USEARE ALSO USE

LINES & FITTINGS LINES & FITTINGS CONT.CONT.

PRECAUTION WHEN WORKING WITH HOSE:PRECAUTION WHEN WORKING WITH HOSE:– SUPPORT END FITTING WHEN REMOVED TO SUPPORT END FITTING WHEN REMOVED TO

PREVENT HOSE FROM CRACKING OR PREVENT HOSE FROM CRACKING OR SPLITTINGSPLITTING

– WHEN INSTALLING HOSE, ENSURE NOT WHEN INSTALLING HOSE, ENSURE NOT TWISTED TO PREVENT LOOSENING OF END TWISTED TO PREVENT LOOSENING OF END FITTING, AND WEAKENING OF HOSE BY FITTING, AND WEAKENING OF HOSE BY OBSERVING LAY-LINEOBSERVING LAY-LINE

TYPICAL HOSE MARKINGTYPICAL HOSE MARKING

LAY LINE OR IDENTIFICATION MARKING LAY LINE OR IDENTIFICATION MARKING SERVE AS GUIDE TO PREVENT TWISTING SERVE AS GUIDE TO PREVENT TWISTING OF HOSE WHEN INSTALLEDOF HOSE WHEN INSTALLED


RIGID LINES NORMALLY ARE OF COPPER, RIGID LINES NORMALLY ARE OF COPPER, ALUMINIUM OR STAINLESS STEELALUMINIUM OR STAINLESS STEEL

COPPER TUBING COPPER TUBING – GOOD CONDUCTOR OF HEATGOOD CONDUCTOR OF HEAT

– TEND TO WORK HARDEN CAUSE BY VIBRATION TEND TO WORK HARDEN CAUSE BY VIBRATION RESULTING IN STRESS FRACTURERESULTING IN STRESS FRACTURE

– COILED TO INCREASE WORK SURFACE IN COILED TO INCREASE WORK SURFACE IN TRANSFERING OF HEAT AND ALLOWS EXPANSIONTRANSFERING OF HEAT AND ALLOWS EXPANSION

– FRACTURE LINE MAY CAUSE OPERATIONAL FRACTURE LINE MAY CAUSE OPERATIONAL PROBLEM SUCH AS AIR INGESTION CAUSING LEAN PROBLEM SUCH AS AIR INGESTION CAUSING LEAN MIXTURE IN FUEL LINE AND PRIMER LINEMIXTURE IN FUEL LINE AND PRIMER LINE

– PERIODIC ANNEALING TO ALLEVIATE WORK PERIODIC ANNEALING TO ALLEVIATE WORK HARDENINGHARDENING


ALUMINIUM TUBING:ALUMINIUM TUBING:– TYPICALLY OF 5052-0 ALUMINIUM ALLOYTYPICALLY OF 5052-0 ALUMINIUM ALLOY

– GOOD CORROSION RESISTANCEGOOD CORROSION RESISTANCE

– EASY TO FABRICATEEASY TO FABRICATE

– LIGHT WEIGHT TO COMPARABLE STRENGTH LIGHT WEIGHT TO COMPARABLE STRENGTH MATERIALMATERIAL

– BUT IT DOES NOT HANDLE HEAT WELL SO IS BUT IT DOES NOT HANDLE HEAT WELL SO IS RARELY USE IN ENGINE COMPARTMENTRARELY USE IN ENGINE COMPARTMENT

STAINLESS STEEL TUBING:STAINLESS STEEL TUBING:– USE FOR HIGH TEMPERATURE CONDITIONSUSE FOR HIGH TEMPERATURE CONDITIONS

– USE AT AREA WHERE CORROSIVE CONDITIONS USE AT AREA WHERE CORROSIVE CONDITIONS EXISTEXIST

– WHERE HIGH STRENGTH IS REQUIREDWHERE HIGH STRENGTH IS REQUIRED

– LIMITED USE IN RECIP. ENGINELIMITED USE IN RECIP. ENGINE– EXTENSIVELY USE IN GAS TURBBINE ENGINEEXTENSIVELY USE IN GAS TURBBINE ENGINE


GUIDELINES FOR INSTALLATION AND GUIDELINES FOR INSTALLATION AND ROUTING OF FUEL LINES:ROUTING OF FUEL LINES:– FUEL LINES SHOULD BE IN SEPARATE SECTION FUEL LINES SHOULD BE IN SEPARATE SECTION

OF AN AIRCRAFTOF AN AIRCRAFT

– IF NOT POSSIBLE, SHOULD BE BELOW IF NOT POSSIBLE, SHOULD BE BELOW ELECTRICAL WIRE BUNDLES, CLAMP TO A/F, ELECTRICAL WIRE BUNDLES, CLAMP TO A/F, NEVER CLAMP TOGETHERNEVER CLAMP TOGETHER

– SUPPORT LINES TO AVOIDS STRAINSUPPORT LINES TO AVOIDS STRAIN– NEVER PULL LINE INTO PLACE BY ITS FITTINGNEVER PULL LINE INTO PLACE BY ITS FITTING– RIGID LINE AT LEAST ONE BEND TO RIGID LINE AT LEAST ONE BEND TO

COMPENSATE FOR SLIGHT MISALIGHTMENT & COMPENSATE FOR SLIGHT MISALIGHTMENT & VIBRATIONVIBRATION

LINES & FITTINGS LINES & FITTINGS CONTCONT..

TYPICAL RIGID LINE TYPICAL RIGID LINE INSTALLATIONINSTALLATION

– ALSO TO RELIEVES TENSION DUE TO ALSO TO RELIEVES TENSION DUE TO EXPANSION AND CONTRACTION CAUSE BY EXPANSION AND CONTRACTION CAUSE BY TEMPERATURE AND PRESSURETEMPERATURE AND PRESSURE

– METAL LINES ELECTRICALLY BONDED AT METAL LINES ELECTRICALLY BONDED AT STRUCTURE ATTACHMENT POINT WITH STRUCTURE ATTACHMENT POINT WITH BONDED CUSHIONED CLAMPSBONDED CUSHIONED CLAMPS

– FUEL LINES INSTALLED TO AVOID BEING USE FUEL LINES INSTALLED TO AVOID BEING USE AS HANDHOLDAS HANDHOLD

– LINES INSTALLED ALONG TOP OR SIDE TO LINES INSTALLED ALONG TOP OR SIDE TO AVOIDS DAMAGE BY CARGOAVOIDS DAMAGE BY CARGO

– SHARP CURVES, STEEP RISE AND STEEP FALLS SHARP CURVES, STEEP RISE AND STEEP FALLS BE AVOIDED TO PREVENT VAPOUR LOCKBE AVOIDED TO PREVENT VAPOUR LOCK


FUEL STRAINERSFUEL STRAINERSREQUIRED BY REGULATION REQUIRED BY REGULATION

PURPOSE TO REMOVE CONTAMINANTS PURPOSE TO REMOVE CONTAMINANTS AND TO DRAIN CONTAMINANTS FROM AND TO DRAIN CONTAMINANTS FROM FUEL SYSTEMSFUEL SYSTEMS

LOWEST POINT BETWEEN TANKS AND LOWEST POINT BETWEEN TANKS AND METERING DEVICE OR EDPMETERING DEVICE OR EDP

LOW POINT COLLECT WATER AND LOW POINT COLLECT WATER AND CONTAMINANTS AT SEDIMENTS BOWLS SO CONTAMINANTS AT SEDIMENTS BOWLS SO THAT IT CAN BE DRAINED FROMTHAT IT CAN BE DRAINED FROM

ALSO ACTS AS A FILTERING BY FINE MESH ALSO ACTS AS A FILTERING BY FINE MESH WIRE SCREEN OR FILTER ELEMENTSWIRE SCREEN OR FILTER ELEMENTS

TYPICAL FUEL STRAINERTYPICAL FUEL STRAINER

CHECK CHECK PERIODICALLY TO PERIODICALLY TO PREVENT PREVENT RESTRICTION OF RESTRICTION OF FUEL FLOW TO FUEL FLOW TO ENGINEENGINE

ENGINE-DRIVEN FUEL PUMPENGINE-DRIVEN FUEL PUMPPRIMARY FUEL PRESSURING PUMP IN PRIMARY FUEL PRESSURING PUMP IN PRESSURE-FEED SYSTEMPRESSURE-FEED SYSTEM

PURPOSE TO ENSURE CONTINEOUS PURPOSE TO ENSURE CONTINEOUS SUPPLY OF FUEL AT PROPER PRESSURE SUPPLY OF FUEL AT PROPER PRESSURE AT ALL ENGINE OPERATIONAT ALL ENGINE OPERATION

USE A POSITIVE-DISPLACEMENT PUMP USE A POSITIVE-DISPLACEMENT PUMP THAT DELIVER SPECIFIC QUANTITY PER THAT DELIVER SPECIFIC QUANTITY PER REVOLUTIONREVOLUTION

VANE-TYPE IS WIDELY USE AS EDPVANE-TYPE IS WIDELY USE AS EDP

MOUNTED ON ENGINE ACCESSORY AND MOUNTED ON ENGINE ACCESSORY AND DRIVEN BY SPLINED SHAFTDRIVEN BY SPLINED SHAFT

TYPICAL VANE-TYPE TYPICAL VANE-TYPE PUMPPUMP

/HOUSING

STEEL

OFF-CENTRE BORE

HOLLOW, STEEL & TURN BY COUPLING

DUE TO ROTOR OFF-SET IN HOUSING, VOLUME INCREASE AND DECREASE THUS DRAW FUEL IN AND FORCE FUEL OUT THE OTHER WAY

THIS PUMP DELIVERED MORE THAN THIS PUMP DELIVERED MORE THAN NEEDED AND IS CONTROLLED BY SPRING-NEEDED AND IS CONTROLLED BY SPRING-LOADED PRESSURE RELIEF VALVELOADED PRESSURE RELIEF VALVE

PREVENT DAMAGE TO METERING DEVICESPREVENT DAMAGE TO METERING DEVICES

EXCESS FUEL BACK TO INLET SIDEEXCESS FUEL BACK TO INLET SIDE

ADJUSTING SCREW TO VARY SPRING ADJUSTING SCREW TO VARY SPRING TENSIONTENSION

THIS VALVE ALSO DAMPENS FUEL THIS VALVE ALSO DAMPENS FUEL PRESSURE FLUCTUATION DURING PRESSURE FLUCTUATION DURING THROTTLE MOVEMENT & MAINTAINS FUEL THROTTLE MOVEMENT & MAINTAINS FUEL PRESSURTE WITHIN SAFE LIMITSPRESSURTE WITHIN SAFE LIMITS

ENGINE-DRIVEN FUEL PUMP ENGINE-DRIVEN FUEL PUMP CONTCONT

VANE-TYPE PUMP WITH VANE-TYPE PUMP WITH BALANCED-TYPE RELIEF VALVEBALANCED-TYPE RELIEF VALVE

ALLOWS ATMOSPHERIC OR CARBURETOR INLET PRESSURE TO ACT ON RELIEF VALVE IN COMBINATION WITH SPRING PRESSURE

WITH LESS FUEL REQUIRE FOR ENGINE AT ALTITUTE, FUEL PRESSURE REQUIRED TO OPEN THE RELIEF VALVE ALSO DECREASE

AUXILIARY FUEL PUMPSAUXILIARY FUEL PUMPSALSO KNOW AS BOOST PUMP, IS TO MAINTAIN ALSO KNOW AS BOOST PUMP, IS TO MAINTAIN POSITIVE FUEL PRESSURE TO INLET SIDE OF EDPPOSITIVE FUEL PRESSURE TO INLET SIDE OF EDPPREVENT PUMP CAVITATION AND VAPOUR LOCKPREVENT PUMP CAVITATION AND VAPOUR LOCKALSO TO PROVIDE REQUIRED FUEL FOR ALSO TO PROVIDE REQUIRED FUEL FOR STARTING AND FUEL TRANSFERRINGSTARTING AND FUEL TRANSFERRINGMAY ALSO SERVE AS BACKUP SOURCE TO EDP MAY ALSO SERVE AS BACKUP SOURCE TO EDP WHEN IT BECOME CLOGGED OR FAILSWHEN IT BECOME CLOGGED OR FAILSOPERATE AUXILARY PUMP IAW ENGINE AND OPERATE AUXILARY PUMP IAW ENGINE AND AIRCRAFT MANUALAIRCRAFT MANUALSOME BOOST PUMP ARE USE INTERMITTENTLY SOME BOOST PUMP ARE USE INTERMITTENTLY WHILE OTHER OPERATE CONTINEOUSWHILE OTHER OPERATE CONTINEOUSSOME UTILISED SWITCH TO VARY FUEL FLOW SOME UTILISED SWITCH TO VARY FUEL FLOW DELIVERY RATEDELIVERY RATE

HAND-OPERATED PUMPHAND-OPERATED PUMPTWO TYPES USE – WOBBLE PUMP OR TWO TYPES USE – WOBBLE PUMP OR MANUAL PRIMERMANUAL PRIMERWOBBLE TYPE CONSIST OF A VANE AND WOBBLE TYPE CONSIST OF A VANE AND DRILLED SHAFT ASSEMBLY, MOUNTED INSIDE DRILLED SHAFT ASSEMBLY, MOUNTED INSIDE PUMP HOUSING, WITH FOUR CHAMBERS WITH PUMP HOUSING, WITH FOUR CHAMBERS WITH ITS OWN FLAPPER VALVEITS OWN FLAPPER VALVESHAFT ASSY. ROTATE BY PUMP HANDLESHAFT ASSY. ROTATE BY PUMP HANDLEBACK AND FORTH OF PUMP HANDLE DRAW BACK AND FORTH OF PUMP HANDLE DRAW FUEL INTO TWO CHAMBERS AND FUEL INTO TWO CHAMBERS AND SIMULTANEOUSLY PUMP FUEL OUT OF THE SIMULTANEOUSLY PUMP FUEL OUT OF THE OTHER TWO CHAMBERSOTHER TWO CHAMBERSDESIGN AND CAPACITY ALLOWS PUMP TO BE DESIGN AND CAPACITY ALLOWS PUMP TO BE USE AS BACKUP, TRANSFERRING FUEL AND USE AS BACKUP, TRANSFERRING FUEL AND PRESSURISED FUEL SYSTEM FOR STARTING PRESSURISED FUEL SYSTEM FOR STARTING AND PRIMING THE ENGINEAND PRIMING THE ENGINE

TYPICAL WOBBLE PUMPTYPICAL WOBBLE PUMP

MANUAL PRIMER INSTALLED IN SECONDARY MANUAL PRIMER INSTALLED IN SECONDARY FUEL LINE COMING OFF FUEL STRAINERFUEL LINE COMING OFF FUEL STRAINERCONSIST OF SMALL CYLINDRICAL TUBE CONSIST OF SMALL CYLINDRICAL TUBE INSIDE COCKPITINSIDE COCKPITPULL TO DRAW FUEL THROUGH CHECK PULL TO DRAW FUEL THROUGH CHECK VALVEVALVEPUSH TO FORCE FUEL THROUGH SECOND PUSH TO FORCE FUEL THROUGH SECOND CHECK VALVE INTO ENGINE CYLINDERSCHECK VALVE INTO ENGINE CYLINDERSON RADIAL ENGINE TO TOP CYLINDER ONLY ON RADIAL ENGINE TO TOP CYLINDER ONLY TO PREVENT LIQUID LOCK OF BOTTOM TO PREVENT LIQUID LOCK OF BOTTOM CYLINDERSCYLINDERSWHEN NOT IN USE, KEEP IT ‘IN’ AND LOCK TO WHEN NOT IN USE, KEEP IT ‘IN’ AND LOCK TO PREVENT SUCTION CAUSING EXTREME RICH PREVENT SUCTION CAUSING EXTREME RICH MIXTURE AND ENGINE RUN ROUGH OR STOPMIXTURE AND ENGINE RUN ROUGH OR STOP

HAND-OPERATED PUMP HAND-OPERATED PUMP CONTCONT

CENTRIFUGAL PUMP IS THE MOST COMMONLY CENTRIFUGAL PUMP IS THE MOST COMMONLY USE BOOST PUMPUSE BOOST PUMPEITHER SUBMERGE OR ATTACHED TO OUTSIDE EITHER SUBMERGE OR ATTACHED TO OUTSIDE OF TANKOF TANKELECTRICALLY OPERATED USING IMPELLER TO ELECTRICALLY OPERATED USING IMPELLER TO BUILD UP PRESSUREBUILD UP PRESSUREWHEN PRESSURE REACHED PREDETERMINED WHEN PRESSURE REACHED PREDETERMINED PRESSURE, FUEL NO LONGER MOVE FROM TANK PRESSURE, FUEL NO LONGER MOVE FROM TANK TO ENGINETO ENGINETHIS MEANS THIS PUMP IS NOT POSITIVE THIS MEANS THIS PUMP IS NOT POSITIVE DISPLACEMENT TYPEDISPLACEMENT TYPEIMPELLER SWIRE FUEL OUTWARD AT HIGH SPEED IMPELLER SWIRE FUEL OUTWARD AT HIGH SPEED TO A DISCHARGE LINE THEN TO ENGINETO A DISCHARGE LINE THEN TO ENGINEHIGH SPEED AND SWIRL FUEL PREVENT HIGH SPEED AND SWIRL FUEL PREVENT POSSIBILITY OF VAPOUR LOCKPOSSIBILITY OF VAPOUR LOCK

AUXILARY PUMP AUXILARY PUMP

TYPICAL CENTRIFUGAL TYPICAL CENTRIFUGAL BOOST PUMPBOOST PUMP

SEAL PREVENT FUEL ENTERING MOTOR SECTION

FUME OR LIQUID FUEL SEEP INTO MOTOR SECTION IS VENTED OVERBOARD

HIGH SPEED FOR TAKE OFF, HIGH POWER SETTING AND HIGH ALTITUDES & LOW SPEED FOR STARTING

PULSATING ELECTRICAL PUMPPULSATING ELECTRICAL PUMPWIDELY USE IN SMALL, LOW WING A/CWIDELY USE IN SMALL, LOW WING A/C

CONSISTS OF:CONSISTS OF:– SOLENOID COIL INSTALLED AROUND A BRASS SOLENOID COIL INSTALLED AROUND A BRASS

TUBE THAT CONNECT A FUEL INLET CHAMBER TUBE THAT CONNECT A FUEL INLET CHAMBER TO A FUEL OUTLET CHAMBERTO A FUEL OUTLET CHAMBER

– STEEL PLUNGER IN CENTRE OF COILSTEEL PLUNGER IN CENTRE OF COIL

– CALIBRATED SPRINGCALIBRATED SPRING– TWO CHECK VALVESTWO CHECK VALVES– A SET OF ELECTRICAL CONTACTA SET OF ELECTRICAL CONTACT– A MAGNETA MAGNET

– A STRAINER, AND A STRAINER, AND

– A WEAK SPRINGA WEAK SPRING

TYPICAL PULSATING-TYPICAL PULSATING-TYPE PUMPTYPE PUMP

USES A CALIBRATED SPRING AND ELECTRO-MAGNET TO FORCE A PLUNGER UP AND DOWN TO PUMP FUEL

THE REPEATED CYCLE CAUSES PUMP TO THE REPEATED CYCLE CAUSES PUMP TO PULSATE RAPIDLY UNTIL PRESSURE BUILDS PULSATE RAPIDLY UNTIL PRESSURE BUILDS UP IN LINEUP IN LINE

WHEN METERING DEVICE BEGIN FUEL WHEN METERING DEVICE BEGIN FUEL USAGE, THE PUMP BEGINS TO PULSATE USAGE, THE PUMP BEGINS TO PULSATE SLOWER TO MAINTAIN A STEADY FUEL SLOWER TO MAINTAIN A STEADY FUEL PRESSUREPRESSURE

NORMALLY INSTALLED PARELLEL WITH EDPNORMALLY INSTALLED PARELLEL WITH EDP

THIS ALLOWS EITHER PUMP TO PROVIDE THIS ALLOWS EITHER PUMP TO PROVIDE PRESSURE REGARDLESS OF OTHER’S PUMP PRESSURE REGARDLESS OF OTHER’S PUMP OPERATIONOPERATION

PULSATING ELECTRICAL PUMP PULSATING ELECTRICAL PUMP CONTCONT

BYPASS VALVEBYPASS VALVEIF AN ENGINE HAS BOTH EDP AND BOOST IF AN ENGINE HAS BOTH EDP AND BOOST PUMP INSTALLED, ONE OF THE PUMP INSTALLED, ONE OF THE FOLLOWING FOLLOWING MUSTMUST BE INCOPORATED: BE INCOPORATED:– BYPASS VALVE WHEN PUMP ARE IN SERIESBYPASS VALVE WHEN PUMP ARE IN SERIES

– CHECK VALVE WHEN PUMP ARE IN PARELLELCHECK VALVE WHEN PUMP ARE IN PARELLEL

PURPOSE TO LET FUEL BYPASS DURING PURPOSE TO LET FUEL BYPASS DURING STARTING OR IN CASE OF PUMP FAILSSTARTING OR IN CASE OF PUMP FAILS

NORMALLY BYPASS VALVE CONSIST OF NORMALLY BYPASS VALVE CONSIST OF CALIBRATED SPRING WHICH OPEN WHEN CALIBRATED SPRING WHICH OPEN WHEN BOOST PUMP EXCEED EDP PRESSURE AND BOOST PUMP EXCEED EDP PRESSURE AND ALLOWS FUEL FLOW DIRECTLY TO ENGINEALLOWS FUEL FLOW DIRECTLY TO ENGINE

TYPICAL PRESSURE RELIEF VALVE TYPICAL PRESSURE RELIEF VALVE INCOPORATING A BYPASS VALVEINCOPORATING A BYPASS VALVE

PURPOSE OF FUEL METERINGPURPOSE OF FUEL METERING TO CONTROL THE AMOUNT OF FUEL BEING TO CONTROL THE AMOUNT OF FUEL BEING

DELIVERED TO THE ENGINE.DELIVERED TO THE ENGINE. BE ABLE TO MIX FUEL/AIR MIXTURE OVER BE ABLE TO MIX FUEL/AIR MIXTURE OVER

WIDE RANGE OF OPERATION AND WIDE RANGE OF OPERATION AND ENVIRONMENTAL CONDITION.ENVIRONMENTAL CONDITION.

IN ADDITION, IT MUST BE ABLE TO ATOMIZE IN ADDITION, IT MUST BE ABLE TO ATOMIZE AND DISTRIBUTE IN A MANNER THAT AND DISTRIBUTE IN A MANNER THAT PROMOTES COMPLETE AND EVEN BURNING IN PROMOTES COMPLETE AND EVEN BURNING IN THE CYLINDERS.THE CYLINDERS.

WITHOUT PROPER ATOMIZATION, FUEL WILL WITHOUT PROPER ATOMIZATION, FUEL WILL NOT VAPOURIZED AND IGNITE.NOT VAPOURIZED AND IGNITE.

ENGINE RUN LEAN EVEN CORRECT AMOUNT ENGINE RUN LEAN EVEN CORRECT AMOUNT OF FUEL IS PRESENT.OF FUEL IS PRESENT.

AND THIS CONDITION WILL CAUSE SEVERE AND THIS CONDITION WILL CAUSE SEVERE DAMAGE TO ENGINE.DAMAGE TO ENGINE.

TYPES OF METERING DEVICESTYPES OF METERING DEVICES

RECIPROCATING ENGINE USE EITHER A RECIPROCATING ENGINE USE EITHER A CARBURETOR OR FUEL INJECTION UNIT.CARBURETOR OR FUEL INJECTION UNIT.CARBURETORS.CARBURETORS.– FLOAT–TYPES CARBURETOR.FLOAT–TYPES CARBURETOR.– PRESSURE-INJECTION CARBURETOR.PRESSURE-INJECTION CARBURETOR.FUEL INJECTION SYSTEM.FUEL INJECTION SYSTEM.– CONTINUOUS SYSTEM.CONTINUOUS SYSTEM.– DIRECT FUEL INJECTION SYSTEM.DIRECT FUEL INJECTION SYSTEM.

METERING PRINCIPLE METERING PRINCIPLE

ALL FUEL METERING DEVICES OPERATE ALL FUEL METERING DEVICES OPERATE ON SOME BASIC LAWS OF PHYSICS AND ON SOME BASIC LAWS OF PHYSICS AND FLUID MECHANIC.FLUID MECHANIC.BERNOULLI’S PRINCIPLES IS WIDELY BERNOULLI’S PRINCIPLES IS WIDELY USED.USED.WHEN AIR PASS THROUGH THE VENTURI, WHEN AIR PASS THROUGH THE VENTURI, IT IS FORCED TO SPEED UP AT THE IT IS FORCED TO SPEED UP AT THE RESTRICTED PORTION OF THE VENTURI.RESTRICTED PORTION OF THE VENTURI.AIR SPEED INCREASES AND PRESSURE AIR SPEED INCREASES AND PRESSURE DECREASE.DECREASE.THE PRESSURE DIFFERENTIAL PRODUCED THE PRESSURE DIFFERENTIAL PRODUCED BY THE VENTURI IS USED TO METER THE BY THE VENTURI IS USED TO METER THE FUEL DELIVERY RATE. FUEL DELIVERY RATE.

TYPICAL VENTURI TUBETYPICAL VENTURI TUBE

FUEL / AIR CHEMISTRYFUEL / AIR CHEMISTRY

TO BURN GASOLINE OR LIQUID FUEL, IT TO BURN GASOLINE OR LIQUID FUEL, IT MUST BE MIXED WITH AIR.MUST BE MIXED WITH AIR.

FOR MIXTURE TO BURN PROPERLY, THE FOR MIXTURE TO BURN PROPERLY, THE RATIO OF FUEL TO AIR MUST BE KEPT RATIO OF FUEL TO AIR MUST BE KEPT WITHIN A CERTAIN RANGE.WITHIN A CERTAIN RANGE.

ACCEPTABLE RANGE IS GOVERN BY THE ACCEPTABLE RANGE IS GOVERN BY THE CHEMICAL COMPOSITION OF CHEMICAL COMPOSITION OF ATMOSPHERE AND THE FUEL.ATMOSPHERE AND THE FUEL.

ATMOSPHERIC CONTENTSATMOSPHERIC CONTENTS78% NITROGEN, 21% OXYGEN AND 1% OTHER 78% NITROGEN, 21% OXYGEN AND 1% OTHER GASES.GASES.NITROGEN IS AN INERT GAS. DOES NOT NITROGEN IS AN INERT GAS. DOES NOT SUPPORT COMBUSTION BUT OXYGEN DOES.SUPPORT COMBUSTION BUT OXYGEN DOES.TO ACHIEVE ANY SPECIFIC FUEL/AIR RATIO, TO ACHIEVE ANY SPECIFIC FUEL/AIR RATIO, AIR DENSITY MUST BE TAKEN INTO AIR DENSITY MUST BE TAKEN INTO CONSIDERATION.CONSIDERATION.DENSITY IS DEFINE AS THE MASS OR WEIGHT DENSITY IS DEFINE AS THE MASS OR WEIGHT OF THE SUBSTANCE PER UNIT VOLUME.OF THE SUBSTANCE PER UNIT VOLUME.DENSITY OF VAPORIZED FUEL AND AIR DENSITY OF VAPORIZED FUEL AND AIR AFFECTED BY TEMPERATURE, PRESSURE AND AFFECTED BY TEMPERATURE, PRESSURE AND HUMIDITY.HUMIDITY.THE ACCURATE METHOD TO DEFINE A THE ACCURATE METHOD TO DEFINE A MIXTURE RATIO IS IN TERMS OF WEIGHT, NOT MIXTURE RATIO IS IN TERMS OF WEIGHT, NOT VOLUME. VOLUME.

PRESSURE AT SEA LEVEL IS 14.7 PSI OR 29.92IN. PRESSURE AT SEA LEVEL IS 14.7 PSI OR 29.92IN. HG. AT A TEMP. OF 59HG. AT A TEMP. OF 59°°F (15F (15°°C), AIR WEIGHT IS C), AIR WEIGHT IS ABOUT 0.0765 LB/CU. FT.ABOUT 0.0765 LB/CU. FT.PRESSURE, TEMPERATURE AND WATER CONTENT PRESSURE, TEMPERATURE AND WATER CONTENT (HUMIDITY) INCREASES, AIR DENSITY OR WEIGHT (HUMIDITY) INCREASES, AIR DENSITY OR WEIGHT DECREASES.DECREASES.IF THE PRESSURE, TEMPERATURE OR WATER IF THE PRESSURE, TEMPERATURE OR WATER CONTENT DECREASED, AIR DENSITY INCREASES.CONTENT DECREASED, AIR DENSITY INCREASES.VOLUME OR MASS OF AIR AND FUEL ENTER THE VOLUME OR MASS OF AIR AND FUEL ENTER THE ENGINE INCREASES, ENGINE PERFORMANCE ENGINE INCREASES, ENGINE PERFORMANCE INCREASES.INCREASES.WHEN WATER CONTENT INCREASE, OXYGEN WHEN WATER CONTENT INCREASE, OXYGEN MOLECULES IS DISPLACED FROM AIRMOLECULES IS DISPLACED FROM AIRIN ADDITION, WATER VAPOUR IS NON-IN ADDITION, WATER VAPOUR IS NON-COMBUSTIBLE AND CAUSES ENGINE’S COMBUSTIBLE AND CAUSES ENGINE’S VOLUMETRIC EFFECIENCY TO DECREASEVOLUMETRIC EFFECIENCY TO DECREASETHIS RESULTED IN ENGINE POWER DECREASE THIS RESULTED IN ENGINE POWER DECREASE REGARDLESS OF ALTITUDEREGARDLESS OF ALTITUDE

ATMOSPHERIC CONTENTS ATMOSPHERIC CONTENTS cont.cont.

FUEL / AIR RATIOFUEL / AIR RATIOIS THE PROPORTION OF FUEL THAT ENTERS AN IS THE PROPORTION OF FUEL THAT ENTERS AN ENGINE.ENGINE.MIXTURE OF 12:1 IS REFERRED TO 12 LB. OF AIR MIXTURE OF 12:1 IS REFERRED TO 12 LB. OF AIR AND 1 LB. OF FUEL BY WEIGHT.AND 1 LB. OF FUEL BY WEIGHT.BURNABLE FUEL/AIR RATIO IS BETWEEN 8:1 AND BURNABLE FUEL/AIR RATIO IS BETWEEN 8:1 AND 16:1.16:1.MIXTURE RATIOS CONSISTING OF LESS THAN 8 MIXTURE RATIOS CONSISTING OF LESS THAN 8 PARTS OF AIR AND MORE THAN 16 PARTS OF AIR PARTS OF AIR AND MORE THAN 16 PARTS OF AIR TYPICALLY RESULT IN INCOMPLETE TYPICALLY RESULT IN INCOMPLETE COMBUSTION.COMBUSTION.PERFECT MIXTURE FOR COMBUSTION IS 0.067 LB PERFECT MIXTURE FOR COMBUSTION IS 0.067 LB FUEL TO 1 LB. OF AIR OR A 15:1 RATIO, ALSO FUEL TO 1 LB. OF AIR OR A 15:1 RATIO, ALSO KNOWN AS STOICHIOMETRIC MIXTURE. KNOWN AS STOICHIOMETRIC MIXTURE. PRODUCES THE HIGHEST COMBUSTION PRODUCES THE HIGHEST COMBUSTION TEMPERATURE. TEMPERATURE.

IT IS NOT NECESSARY AN IDEAL MIXTURE IT IS NOT NECESSARY AN IDEAL MIXTURE FOR PROPER ENGINE OPERATION.FOR PROPER ENGINE OPERATION.REASON IS RECIPROCATING ENGINE NOT REASON IS RECIPROCATING ENGINE NOT 100% EFFICIENT SO LESS AIR IS REQUIRED 100% EFFICIENT SO LESS AIR IS REQUIRED TO PROVIDE ADEQUATE ENGINE TO PROVIDE ADEQUATE ENGINE PERFORMANCE.PERFORMANCE.EXAMPLE:- AN ENGINE DEVELOP MAXIMUM EXAMPLE:- AN ENGINE DEVELOP MAXIMUM POWER WITH MIXTURE OF 12:1 AND POWER WITH MIXTURE OF 12:1 AND OPERATES AT MAX. ECONOMY WITH A 14:1 OPERATES AT MAX. ECONOMY WITH A 14:1 FUEL/AIR RATIO WHICH IS CLOSE TO FUEL/AIR RATIO WHICH IS CLOSE TO STOICHOMETRIC OR 15:1. STOICHOMETRIC OR 15:1.

FUEL / AIR RATIO FUEL / AIR RATIO cont.cont.

MIXTURE RATIO TERMINOLOGYMIXTURE RATIO TERMINOLOGYTWO COMMON TERM OFTEN USED TO DESCRIBE TWO COMMON TERM OFTEN USED TO DESCRIBE FUEL/AIR MIXTURE ARE LEAN AND RICH. FUEL/AIR MIXTURE ARE LEAN AND RICH. LEAN - MORE AIR LESS FUEL.LEAN - MORE AIR LESS FUEL.RICH - MORE FUEL LESS AIR.RICH - MORE FUEL LESS AIR.FULL RICH: - MAX. FUEL FLOW WITH CONTROL FULL RICH: - MAX. FUEL FLOW WITH CONTROL FULLY FORWARD POSITION AND NORMALLY FULLY FORWARD POSITION AND NORMALLY USED WHEN OPERATING A/C ON GROUND.USED WHEN OPERATING A/C ON GROUND.IF OPERATED AT HIGH ELEVATION AIRPORT, IF OPERATED AT HIGH ELEVATION AIRPORT, MIXTURE SHOULD LEAN SLIGHTLY TO MIXTURE SHOULD LEAN SLIGHTLY TO COMPENSATE FOR LESS DENSE AIR AND HELPS COMPENSATE FOR LESS DENSE AIR AND HELPS PREVENT OVERLY RICH MIXTURE AND SPARK PREVENT OVERLY RICH MIXTURE AND SPARK PLUG FOULING.PLUG FOULING.IDLE–CUT OFF CONTROL IS TO COMPLETELY IDLE–CUT OFF CONTROL IS TO COMPLETELY CUTS OFF THE FUEL FLOW TO THE ENGINE BY CUTS OFF THE FUEL FLOW TO THE ENGINE BY PULLING MIXTURE CONTROL FULLY OUT OR AFT PULLING MIXTURE CONTROL FULLY OUT OR AFT POSITION.POSITION.

LEAN BEST POWER AND RICH BEST POWER: IS THE LEAN BEST POWER AND RICH BEST POWER: IS THE RANGE OF MIXTURE RATIO THAT PROVIDE MAX. RPM RANGE OF MIXTURE RATIO THAT PROVIDE MAX. RPM AND MANIFOLD PRESSURE FOR A GIVEN THROTTLE AND MANIFOLD PRESSURE FOR A GIVEN THROTTLE SETTING. SETTING. BOTH PRODUCE THE SAME ENGINE PERFORMANCE, BOTH PRODUCE THE SAME ENGINE PERFORMANCE, LEAN BEST POWER USES SLIGHTLY LESS FUEL THAN LEAN BEST POWER USES SLIGHTLY LESS FUEL THAN RICH BEST POWER. RICH BEST POWER. BEST ECONOMY : IS THE RANGE OF MIXTURE RATIO BEST ECONOMY : IS THE RANGE OF MIXTURE RATIO THAT DEVELOP GREATEST AMOUNT OF POWER FOR THAT DEVELOP GREATEST AMOUNT OF POWER FOR LEAST AMOUNT OF FUEL FLOW.LEAST AMOUNT OF FUEL FLOW.OBTAINED BY LEANING UNTIL THE HIGHEST EGT AND OBTAINED BY LEANING UNTIL THE HIGHEST EGT AND RPM IS OBTAINED WITH THROTTLE IN A SET POSITIONRPM IS OBTAINED WITH THROTTLE IN A SET POSITIONPROLONG USE MAY EXCEED RATED TEMPERATURE PROLONG USE MAY EXCEED RATED TEMPERATURE LIMITLIMITMOST MANUFACTURER RECOMMEND BEST POWER MOST MANUFACTURER RECOMMEND BEST POWER MIXTURE RATIO FOR EXTENDED OPERATIONMIXTURE RATIO FOR EXTENDED OPERATION

MIXTURE RATIO TERMINOLOGYMIXTURE RATIO TERMINOLOGYCONTCONT

LEANING TECHNIQUES LEANING TECHNIQUES TO ACHIEVE A DESIRED MIXTURE, TO ACHIEVE A DESIRED MIXTURE, MIXTURE CONTROL MUST BE ADJUSTED MIXTURE CONTROL MUST BE ADJUSTED TO COMPENSATE FOR VARYING TO COMPENSATE FOR VARYING CONDITION SUCH AS DURING CLIMB CONDITION SUCH AS DURING CLIMB WHERE MIXTURE IS LEANED.WHERE MIXTURE IS LEANED.TO DETERMINE IF PROPER MIXTURE RATIO TO DETERMINE IF PROPER MIXTURE RATIO HAVE ACHIEVE, ENGINE INSTRUMENTS HAVE ACHIEVE, ENGINE INSTRUMENTS SUCH AS TACHOMETER, MANIFOLD SUCH AS TACHOMETER, MANIFOLD PRESSURE AND EGT IS USED.PRESSURE AND EGT IS USED.ADJUST MIXTURE CONTROL OUTWARD TO ADJUST MIXTURE CONTROL OUTWARD TO ACHIEVE RPM AT ITS MAXIMUM VALUE, ACHIEVE RPM AT ITS MAXIMUM VALUE, THAT IS BEST ECONOMY RATIO.THAT IS BEST ECONOMY RATIO.BEST POWER IS ACHIEVE BY ENRICHEN BEST POWER IS ACHIEVE BY ENRICHEN THE MIXTURE SLIGHTLY, THIS IS USED ON THE MIXTURE SLIGHTLY, THIS IS USED ON FIXED-PITCH PROPELLER A/C.FIXED-PITCH PROPELLER A/C.

LEANING TECHNIQUESLEANING TECHNIQUES CONT. CONT. CONSTANT SPEED PROPELLER, MANIFOLD CONSTANT SPEED PROPELLER, MANIFOLD PRESSURE IS USED BECAUSE PROPELLER PRESSURE IS USED BECAUSE PROPELLER GOVERNOR KEEP THE PROPELLER SPEED GOVERNOR KEEP THE PROPELLER SPEED CONSTANT.CONSTANT.MOST ACCURATE METHOD OF LEANING IS MOST ACCURATE METHOD OF LEANING IS CHECKING THE EGT.CHECKING THE EGT.BY MONITORING EGT, YOU CAN SET THE BY MONITORING EGT, YOU CAN SET THE FUEL/AIR MIXTURE FOR BEST ECONOMY FUEL/AIR MIXTURE FOR BEST ECONOMY OR BEST POWER.OR BEST POWER.COMMON METHOD OF SETTING BEST COMMON METHOD OF SETTING BEST POWER IS BY SETTING EGT TO MAX. THEN POWER IS BY SETTING EGT TO MAX. THEN ENRICHEN IT TO 25ENRICHEN IT TO 25°°F COOLER THAN PEAK F COOLER THAN PEAK EGT.EGT.

SPECIFIC FUEL CONSUMPTIONSPECIFIC FUEL CONSUMPTIONTO DETERMINE THE ENGINE EFFICIENCY.TO DETERMINE THE ENGINE EFFICIENCY.SFC IS THE NUMBER OF LBS OF FUEL SFC IS THE NUMBER OF LBS OF FUEL BURNED/HR TO PRODUCE 1 HP.BURNED/HR TO PRODUCE 1 HP.MOST MODERN A/C ENGINE HAVE A MOST MODERN A/C ENGINE HAVE A BRAKE SFC BETWEEN 0.4 – 0.5 LBS/HP/HR.BRAKE SFC BETWEEN 0.4 – 0.5 LBS/HP/HR.TO VERIFY SFC VALUE AGAINST TO VERIFY SFC VALUE AGAINST MANUFACTURER’S SPECIFIED VALUE AND MANUFACTURER’S SPECIFIED VALUE AND PROPER OPERATION OF THE FUEL PROPER OPERATION OF THE FUEL METERING DEVICE, ENGINE HAS TO BE METERING DEVICE, ENGINE HAS TO BE RUN UP.RUN UP.Eg. RUN ENGINE AT A GIVEN RPM FOR Eg. RUN ENGINE AT A GIVEN RPM FOR SPECIFIC PERIOD AND MONITORING THE SPECIFIC PERIOD AND MONITORING THE FUEL FLOW, YOU CAN DETERMINE THE FUEL FLOW, YOU CAN DETERMINE THE ENGINE’S SFC.ENGINE’S SFC.MFG. PROVIDE ENGINE’S SFC TO SIMPLIFY MFG. PROVIDE ENGINE’S SFC TO SIMPLIFY VERIFICATION PROCESSVERIFICATION PROCESS

TYPICAL SFC CHARTTYPICAL SFC CHART

DETONATION & PREIGNITIONDETONATION & PREIGNITION NORMAL COMBUSTION – COMPLETE AND EVEN NORMAL COMBUSTION – COMPLETE AND EVEN COMBUSTION OF MIXTURE THAT CAUSES A SMOOTH COMBUSTION OF MIXTURE THAT CAUSES A SMOOTH BUILDUP OF PRESSURE AND TEMPERATURE TO GIVE A BUILDUP OF PRESSURE AND TEMPERATURE TO GIVE A MAXIMUN POWER.MAXIMUN POWER.DETONATION :- UNCONTROLLED, EXPLOSIVE IGNITION DETONATION :- UNCONTROLLED, EXPLOSIVE IGNITION OF FUEL / AIR MIXTURE IN A CYLINDER. OF FUEL / AIR MIXTURE IN A CYLINDER. THIS CAUSES HIGH TEMP. AND PRESS. WHICH LEAD TO THIS CAUSES HIGH TEMP. AND PRESS. WHICH LEAD TO ENGINE RUN ROUGH, OVERHEATING AND POWER LOSS.ENGINE RUN ROUGH, OVERHEATING AND POWER LOSS.DAMAGE OR FAILURE OF PISTON, CYLINDERS AND DAMAGE OR FAILURE OF PISTON, CYLINDERS AND VALVES CAN HAPPEN.VALVES CAN HAPPEN.HIGH PRESS. AND TEMP. WITH HIGH TURBULENCE HIGH PRESS. AND TEMP. WITH HIGH TURBULENCE GENERATED CAUSE A “HAMMERING” OR “SCRUBBING” GENERATED CAUSE A “HAMMERING” OR “SCRUBBING” ACTION IN A CYLINDER THAT CAN BURN A HOLE ACTION IN A CYLINDER THAT CAN BURN A HOLE THROUGH PISTON.THROUGH PISTON.AN AUDIBLE “KNOCKING” CAN BE IDENTIFIED IF NOT AN AUDIBLE “KNOCKING” CAN BE IDENTIFIED IF NOT BECAUSE OF THE NOISE CREATED BY THE PROPELLER.BECAUSE OF THE NOISE CREATED BY THE PROPELLER.CAUSED BY SEVERAL FACTORS INCLUDING LOW CAUSED BY SEVERAL FACTORS INCLUDING LOW GRADE FUEL AND EXCESSIVELY LEAN MIXTURE WHICH GRADE FUEL AND EXCESSIVELY LEAN MIXTURE WHICH IN TURN INCREASES THE CHANCES OF DETONATION.IN TURN INCREASES THE CHANCES OF DETONATION.

PREIGNITIONPREIGNITIONPREIGNITION IS WHEN FUEL/AIR MIXTURE IGNITES TOO PREIGNITION IS WHEN FUEL/AIR MIXTURE IGNITES TOO SOON AND CAUSED BY HOT SPOTS IN THE CYLINDER SOON AND CAUSED BY HOT SPOTS IN THE CYLINDER THAT IGNITE THE MIXTURE BEFORE THE SPARK PLUGS THAT IGNITE THE MIXTURE BEFORE THE SPARK PLUGS FIRE.FIRE.HOT SPOT CAN BE CAUSED BY CARBON DEPOSITS, HOT SPOT CAN BE CAUSED BY CARBON DEPOSITS, OVERHEAT VALVE EDGES (FEATHERED VALVE), SILICA OVERHEAT VALVE EDGES (FEATHERED VALVE), SILICA DEPOSIT ON THE SPARK PLUG AND RED-HOT SPARK DEPOSIT ON THE SPARK PLUG AND RED-HOT SPARK PLUG ELECTRODE.PLUG ELECTRODE.HOT SPOTS ARE CAUSED BY POOR ENGINE COOLING, HOT SPOTS ARE CAUSED BY POOR ENGINE COOLING, DIRTY INTAKE AIR FILTER AND SHUTTING DOWN DIRTY INTAKE AIR FILTER AND SHUTTING DOWN ENGINE AT HIGH RPM.ENGINE AT HIGH RPM.PREIGNITION MAY ALSO CAUSE ENGINE TO CONTINUES PREIGNITION MAY ALSO CAUSE ENGINE TO CONTINUES TO RUN AFTER THE IGNITION IS TURN OFF.TO RUN AFTER THE IGNITION IS TURN OFF.PREIGNITION AND DETONATION CAN OCCUR PREIGNITION AND DETONATION CAN OCCUR SIMULTANEOUSLY, BUT DIFFICULT TO DISTINGUISH SIMULTANEOUSLY, BUT DIFFICULT TO DISTINGUISH BETWEEN THE TWO.BETWEEN THE TWO.EITHER CONDITION, THE ENGINE RUN ROUGH WITH EITHER CONDITION, THE ENGINE RUN ROUGH WITH HIGH OPERATING TEMPERATURE.HIGH OPERATING TEMPERATURE.

BACKFIRE AND AFTERFIREBACKFIRE AND AFTERFIRELEAN FUEL/AIR MIXTURE CAN RESULT IN LEAN FUEL/AIR MIXTURE CAN RESULT IN DETONATION.DETONATION.FUEL/AIR MIXTURE SO LEAN THAT IT FUEL/AIR MIXTURE SO LEAN THAT IT BURNS AT EXTREMELY SLOW RATE.BURNS AT EXTREMELY SLOW RATE.FUEL/AIR STILL BURNING WHEN INTAKE FUEL/AIR STILL BURNING WHEN INTAKE VALVE OPEN AND ALLOW FRESH MIXTURE VALVE OPEN AND ALLOW FRESH MIXTURE TO ENTER.TO ENTER.IT IGNITED BEFORE THE INTAKE VALVE IT IGNITED BEFORE THE INTAKE VALVE CLOSED AND ENGINE BACKFIRE THROUGH CLOSED AND ENGINE BACKFIRE THROUGH THE INDUCTION MANIFOLD, FUEL THE INDUCTION MANIFOLD, FUEL METERING UNIT AND OUT THE INDUCTION METERING UNIT AND OUT THE INDUCTION SYSTEM.SYSTEM.BACKFIRING ALWAYS OCCUR IN THE BACKFIRING ALWAYS OCCUR IN THE INDUCTION SYSTEM.INDUCTION SYSTEM.

AFTERFIREAFTERFIRE

OCCURS IN THE EXHAUST SYSTEM. OCCURS IN THE EXHAUST SYSTEM.

RESULT FROM EXCESSIVE RICH FUEL/AIR RESULT FROM EXCESSIVE RICH FUEL/AIR MIXTURE.MIXTURE.

RICH MIXTURE WITH LACK OF OXYGEN RICH MIXTURE WITH LACK OF OXYGEN BURN SLOWLY.BURN SLOWLY.

MIXTURE NOT COMPLETELY BURNS WHEN MIXTURE NOT COMPLETELY BURNS WHEN EXHAUST VALVE OPEN, WILL MIX WITH AIR EXHAUST VALVE OPEN, WILL MIX WITH AIR IN THE EXHAUST AND CONTINUE TO BURN.IN THE EXHAUST AND CONTINUE TO BURN.

CAUSES FLAME TO APPEAR AS UNBURNED CAUSES FLAME TO APPEAR AS UNBURNED MIXTURE EXITS THE EXHAUST STACKS.MIXTURE EXITS THE EXHAUST STACKS.

CARBURETORCARBURETORCLASSIFIED AS :- CLASSIFIED AS :- – UPDRAFT - AIR FLOWS UPWARDUPDRAFT - AIR FLOWS UPWARD– DOWNDRAFT - AIR FLOWS DOWNWARD.DOWNDRAFT - AIR FLOWS DOWNWARD.

MOST A/C USED UPDRAFT CARBURETOR MOST A/C USED UPDRAFT CARBURETOR MOUNTED UNDER THE ENGINE.MOUNTED UNDER THE ENGINE.MIXED AND ATOMIZE FUEL AND AIR TO MIXED AND ATOMIZE FUEL AND AIR TO ESTABLISHED OPTIMUM FUEL/AIR RATIO AND ESTABLISHED OPTIMUM FUEL/AIR RATIO AND DISTRIBUTED AS EVENLY AS POSSIBLE TO DISTRIBUTED AS EVENLY AS POSSIBLE TO EACH CYLINDER OF THE ENGINE.EACH CYLINDER OF THE ENGINE.IN REALITY, BOTH VOLUME AND RATIO OF IN REALITY, BOTH VOLUME AND RATIO OF FUEL/AIR CHARGE ENTER THE CYLINDER FUEL/AIR CHARGE ENTER THE CYLINDER VARIES BECAUSE OF THE DIFFERENT VARIES BECAUSE OF THE DIFFERENT DISTANCE TO TRAVEL THROUGH THE DISTANCE TO TRAVEL THROUGH THE INDUCTION MANIFOLD. INDUCTION MANIFOLD.

CARBURETOR VENTURI PRINCIPLES CARBURETOR VENTURI PRINCIPLES

CARBURETOR DEPENDS ON DIFFERENTIAL CARBURETOR DEPENDS ON DIFFERENTIAL PRESSURE CREATED AT THE VENTURI PRESSURE CREATED AT THE VENTURI THROAT TO MEASURE THE AMOUNT OF AIR THROAT TO MEASURE THE AMOUNT OF AIR DELIVERED AND METERED THE PROPER DELIVERED AND METERED THE PROPER AMOUNT OF FUEL.AMOUNT OF FUEL.AIR FLOWS THROUGH THE VENTURI, AIR FLOWS THROUGH THE VENTURI, INCREASES IN SPEED (VELOCITY) AND INCREASES IN SPEED (VELOCITY) AND PRESSURE DECREASES.PRESSURE DECREASES.THROTTLE VALVE (BUTTERFLY VALVE) THROTTLE VALVE (BUTTERFLY VALVE) CONTROL THE VOLUME OF AIR PASSES CONTROL THE VOLUME OF AIR PASSES THROUGH THE VENTURI.THROUGH THE VENTURI.VALVE IS A FLAT CIRCULAR PIECE OF VALVE IS A FLAT CIRCULAR PIECE OF METAL INSTALLED BETWEEN VENTURI AND METAL INSTALLED BETWEEN VENTURI AND ENGINE.ENGINE.

CARBURETOR VENTURI PRINCIPLESCARBURETOR VENTURI PRINCIPLES CONT CONT

WHEN VALVE FULLY OPEN, VENTURI LIMITS WHEN VALVE FULLY OPEN, VENTURI LIMITS THE VOLUME OF AIR ENTERING THE THE VOLUME OF AIR ENTERING THE ENGINE.ENGINE.THROTTLE VALVE CONTROLLED FROM THE THROTTLE VALVE CONTROLLED FROM THE COCKPIT. COCKPIT. PUSH FORWARD, VALVE OPEN ENGINE PUSH FORWARD, VALVE OPEN ENGINE POWER INCREASE.POWER INCREASE.PULLED BACKWARD, VALVE CLOSE POWER PULLED BACKWARD, VALVE CLOSE POWER DECREASE.DECREASE.SIZE AND SHAPE OF VENTURI VARIES WITH SIZE AND SHAPE OF VENTURI VARIES WITH REQUIREMENT.REQUIREMENT.

TYPICAL VENTURI & TYPICAL VENTURI & BUTTERFLY ASSEMBLYBUTTERFLY ASSEMBLY

CARBURETOR SYSTEMCARBURETOR SYSTEMTO PROVIDE PROPER ENGINE OPERATION TO PROVIDE PROPER ENGINE OPERATION UNDER VARIOUS ENGINE LOAD, SPEED UNDER VARIOUS ENGINE LOAD, SPEED AND AIR DENSITIES.AND AIR DENSITIES.FIVE MAIN SYSTEM :-FIVE MAIN SYSTEM :-– MAIN METERING.MAIN METERING.– IDLING.IDLING.– MIXTURE CONTROL.MIXTURE CONTROL.– ACCELERATING.ACCELERATING.

– POWER ENRICHMENT OR ECONOMIZERPOWER ENRICHMENT OR ECONOMIZER..TWO TYPES OF CARBURETOR TO BE TWO TYPES OF CARBURETOR TO BE DISCUSSED:DISCUSSED:– FLOAT-TYPE CARBURETOR.FLOAT-TYPE CARBURETOR.– PRESSURE INJECTION CARBURETOR. PRESSURE INJECTION CARBURETOR.

FLOAT–TYPE CARBURETORFLOAT–TYPE CARBURETORCONSIST OF :- CONSIST OF :- – FLOAT CHAMBER – WHERE FUEL IS FLOAT CHAMBER – WHERE FUEL IS

STORED.STORED.

– NEEDLE VALVE – CONTROLLED AMOUNT NEEDLE VALVE – CONTROLLED AMOUNT OF FUEL INTO FLOAT CHAMBER.OF FUEL INTO FLOAT CHAMBER.

– NEEDLE SEAT – SEAT THE NEEDLES AND NEEDLE SEAT – SEAT THE NEEDLES AND STOP FUEL FLOW.STOP FUEL FLOW.

– FLOAT – CLOSES THE NEEDLE VALVE.FLOAT – CLOSES THE NEEDLE VALVE.– FUEL SCREEN – FILTER FUEL BEFORE FUEL SCREEN – FILTER FUEL BEFORE

ENTERING FLOAT CHAMBER.ENTERING FLOAT CHAMBER.

TYPICAL FLOAT-TYPE TYPICAL FLOAT-TYPE CARBURETORCARBURETOR

FLOAT IS CONSTRUCTED OF BRASS OR FLOAT IS CONSTRUCTED OF BRASS OR COMPOSITE MATERIALCOMPOSITE MATERIAL

WITH BRASS, IT IS HOLLOW WITH AIR SEAL INSIDE WITH BRASS, IT IS HOLLOW WITH AIR SEAL INSIDE TO PROVIDE BUOYANCYTO PROVIDE BUOYANCY

COMPOSITE IS OF SOLID PIECE, WITH TRAPPED COMPOSITE IS OF SOLID PIECE, WITH TRAPPED AIR IN THE POROUS COMPOSITE MATERIAL AIR IN THE POROUS COMPOSITE MATERIAL PROVIDING BUOYANCYPROVIDING BUOYANCY

VENT TO ALLOWS AIR TO ENTER AND LEAVE VENT TO ALLOWS AIR TO ENTER AND LEAVE FLOAT CHAMBER AS FUEL LEVEL RISE AND FALLFLOAT CHAMBER AS FUEL LEVEL RISE AND FALL

VENT IS OPEN TO ATMOSPHERE OR INTO AIR VENT IS OPEN TO ATMOSPHERE OR INTO AIR INTAKE TO MAINTAIN SAME PRESSURE AS INTAKE TO MAINTAIN SAME PRESSURE AS ATMOSPHERICATMOSPHERIC

FLOAT–TYPE CARBURETOR FLOAT–TYPE CARBURETOR cont.cont.

MAIN METERINGMAIN METERING

PURPOSE IS TO SUPPLY THE CORRECT PURPOSE IS TO SUPPLY THE CORRECT AMOUNT OF FUEL TO THE ENGINE AT ALL AMOUNT OF FUEL TO THE ENGINE AT ALL SPEEDS ABOVE IDLE. SPEEDS ABOVE IDLE. MAIN METERING SYSTEM COMPRISED OF:-MAIN METERING SYSTEM COMPRISED OF:-– ONE OR MORE VENTURI TUBES.ONE OR MORE VENTURI TUBES.– MAIN METERING JET.MAIN METERING JET.– DISCHARGE NOZZLE.DISCHARGE NOZZLE.– THROTTLE VALVE.THROTTLE VALVE.

FUEL METERING BEGIN AT VENTURIFUEL METERING BEGIN AT VENTURISOME CARBURETOR WITH SINGLE VENTURI SOME CARBURETOR WITH SINGLE VENTURI UNABLE TO CREATE ENOUGH PRESSURE DROPUNABLE TO CREATE ENOUGH PRESSURE DROPBOOST VENTURI FITTED INSIDE OR JUST PRIOR BOOST VENTURI FITTED INSIDE OR JUST PRIOR TO THE PRIMARY VENTURITO THE PRIMARY VENTURIDISCHARGE NOZZLE BETWEEN FLOAT CHAMBER DISCHARGE NOZZLE BETWEEN FLOAT CHAMBER AND VENTURI, DELIVERS FUEL TO INTAKE AIRAND VENTURI, DELIVERS FUEL TO INTAKE AIRAT REST, FUEL SAME LEVEL IN CHAMBER AND AT REST, FUEL SAME LEVEL IN CHAMBER AND DISCHARGE NOZZLEDISCHARGE NOZZLESOME FLOAT MAINTAIN A LEVEL 1/8” BELOW SOME FLOAT MAINTAIN A LEVEL 1/8” BELOW DISCHARGE NOZZLE – FUEL METERING HEADDISCHARGE NOZZLE – FUEL METERING HEADPURPOSE TO PREVENT FUEL LEAK WHEN ENGINE PURPOSE TO PREVENT FUEL LEAK WHEN ENGINE SHUT DOWNSHUT DOWN

MAIN METERING MAIN METERING cont.cont.

PRIMARY COMPONENTS OF PRIMARY COMPONENTS OF FLOAT-TYPE CARBURETORFLOAT-TYPE CARBURETOR

FUEL METERING FUEL METERING HEAD 1/8”HEAD 1/8”

THE OPERATION OF DISCHARGE NOZZLE IS THE OPERATION OF DISCHARGE NOZZLE IS BASED ON THE PRESSURE DIFFERENCE BASED ON THE PRESSURE DIFFERENCE BETWEEN THE FLOAT CHAMBER (P1) AND BETWEEN THE FLOAT CHAMBER (P1) AND THE VENTURI (P2).THE VENTURI (P2).

PRESSURE DIFFERENTIAL FORCES THE PRESSURE DIFFERENTIAL FORCES THE FUEL TO FLOW-OUT (DISCHARGE) INTO THE FUEL TO FLOW-OUT (DISCHARGE) INTO THE AIRSTREAM. AIRSTREAM.

THE GREATER THE PRESSURE DIFFERENCE THE GREATER THE PRESSURE DIFFERENCE BETWEEN THE FLOAT CHAMBER AND THE BETWEEN THE FLOAT CHAMBER AND THE VENTURI, THE MORE FUEL IS DISCHARGED.VENTURI, THE MORE FUEL IS DISCHARGED.

MAXIMUM FUEL FLOW LIMITED BY THE SIZE MAXIMUM FUEL FLOW LIMITED BY THE SIZE OF MAIN METERING JET. OF MAIN METERING JET.


TYPICAL DISCHARGE NOZZLETYPICAL DISCHARGE NOZZLE

PRESSURE DIFFERENTIAL OF 0.5”HG. IS PRESSURE DIFFERENTIAL OF 0.5”HG. IS REQUIRED TO RAISE FUEL PASS FUEL REQUIRED TO RAISE FUEL PASS FUEL METERING HEADMETERING HEADHIGH POWER, ENOUGH PRESSURE HIGH POWER, ENOUGH PRESSURE DIFFERENCE TO ENSURE CONTINEOUS DIFFERENCE TO ENSURE CONTINEOUS FUEL FLOWFUEL FLOWLOW ENGINE SPEED HAMPER BY SURFACE LOW ENGINE SPEED HAMPER BY SURFACE TENSIONTENSIONSURFACE TENSION IS A PHYSICAL SURFACE TENSION IS A PHYSICAL PROPERTY OF FLUID THAT TEND TO HOLD PROPERTY OF FLUID THAT TEND TO HOLD TOGETHER INSTEAD OF BREAK OUT OR TOGETHER INSTEAD OF BREAK OUT OR SPREAD OUTSPREAD OUTAN EXAMPLE IS SEEN WHEN A CONTAINER AN EXAMPLE IS SEEN WHEN A CONTAINER IS SLIGHTLY OVERFILLEDIS SLIGHTLY OVERFILLED


AIR BLEED INCORPORATED INTO THE AIR BLEED INCORPORATED INTO THE METERING SYSTEM TO DECREASED FUEL METERING SYSTEM TO DECREASED FUEL SURFACE TENSION THAT TENDS TO SURFACE TENSION THAT TENDS TO CAUSE FUEL TO FLOW INTERMITTENTLY IN CAUSE FUEL TO FLOW INTERMITTENTLY IN DROPLET FORM.DROPLET FORM.ITS CONSISTS OF A PASSAGE, WITH ITS CONSISTS OF A PASSAGE, WITH SMALL CALIBRATED ORIFICE.SMALL CALIBRATED ORIFICE.ONE END AT DISCHARGE NOZZLE AND ONE END AT DISCHARGE NOZZLE AND OTHER END INTO AN AREA BEHIND OTHER END INTO AN AREA BEHIND VENTURI WHERE AIR IS NEAR VENTURI WHERE AIR IS NEAR ATMOSPHERICATMOSPHERICBLEED AIR SYSTEM FUNCTION CAN BE BLEED AIR SYSTEM FUNCTION CAN BE DEMONSTRATE BY SUCKING FLUID WITH DEMONSTRATE BY SUCKING FLUID WITH STRAW THAT HAS A PIN HOLESTRAW THAT HAS A PIN HOLE


TYPICAL AIR BLEED TYPICAL AIR BLEED EXPERIMENTEXPERIMENT

LOW PRESSURE AT THE DISCHARGE NOZZLE LOW PRESSURE AT THE DISCHARGE NOZZLE DRAWS FUEL OUT OF THE FLOAT CHAMBER DRAWS FUEL OUT OF THE FLOAT CHAMBER AND BLEED AIR FROM BEHIND THE VENTURI.AND BLEED AIR FROM BEHIND THE VENTURI.BLEED AIR AND FUEL MIX IN THE DISCHARGE BLEED AIR AND FUEL MIX IN THE DISCHARGE NOZZLE, CREATING AN EMULSION OR NOZZLE, CREATING AN EMULSION OR MIXTURE, WHICH LOWER THE FUEL’S MIXTURE, WHICH LOWER THE FUEL’S DENSITY AND HELP BREAK UP ITS SURFACE DENSITY AND HELP BREAK UP ITS SURFACE TENSION.TENSION.BY DISRUPTING THIS SURFACE TENSION, BY DISRUPTING THIS SURFACE TENSION, FUEL DISCHARGE FROM NOZZLE IS IN FINE FUEL DISCHARGE FROM NOZZLE IS IN FINE UNIFORM SPRAY WHICH PROMOTES UNIFORM SPRAY WHICH PROMOTES VAPORIZATION.VAPORIZATION.IF AIR BLEED PASSAGE PARTIALLY OR IF AIR BLEED PASSAGE PARTIALLY OR COMPLETELY BLOCKED, THE MIXTURE WILL COMPLETELY BLOCKED, THE MIXTURE WILL BECOME EXCESSIVELY RICH AT HIGHER BECOME EXCESSIVELY RICH AT HIGHER POWER SETTINGS.POWER SETTINGS.


TYPICAL AIR BLEEDTYPICAL AIR BLEED

IDLING SYSTEMIDLING SYSTEMTHE LOWEST POSSIBLE RPM THE ENGINE CAN THE LOWEST POSSIBLE RPM THE ENGINE CAN MAINTAIN IN SMOOTH RUNNING WITHOUT THE MAINTAIN IN SMOOTH RUNNING WITHOUT THE TENDENCY TO VIBRATE OR QUIT.TENDENCY TO VIBRATE OR QUIT.THROTTLE VALVE IS IN NEARLY CLOSED POSITION. THROTTLE VALVE IS IN NEARLY CLOSED POSITION. AIR IN THE VENTURI IS REDUCED, IT REDUCES AIR IN THE VENTURI IS REDUCED, IT REDUCES PRESSURE DIFFERENTIAL.PRESSURE DIFFERENTIAL.INSUFFICIENT FUEL CAN BE DRAWN FROM MAIN INSUFFICIENT FUEL CAN BE DRAWN FROM MAIN DISCHARGE NOZZLE.DISCHARGE NOZZLE.SERIES OF TWO OR THREE SMALL PASSAGES SERIES OF TWO OR THREE SMALL PASSAGES PROVIDED IN THE CARBURETOR BARREL NEAR THE PROVIDED IN THE CARBURETOR BARREL NEAR THE EDGE OF THE THROTTLE VALVE WHERE A SMALL EDGE OF THE THROTTLE VALVE WHERE A SMALL AMOUNT OF AIR CAN STILL FLOW.AMOUNT OF AIR CAN STILL FLOW.THIS IS CALLED ‘IDLE DISCHARGE PORTS’ OR ‘IDLE THIS IS CALLED ‘IDLE DISCHARGE PORTS’ OR ‘IDLE JETS’ AND ARE CONNECTED BY IDLE EMULSION TUBE JETS’ AND ARE CONNECTED BY IDLE EMULSION TUBE TO AN ANNULUS THAT DRAWS FUEL FROM THE TO AN ANNULUS THAT DRAWS FUEL FROM THE OUTLET OF THE MAIN METERING JET.OUTLET OF THE MAIN METERING JET.THE EMULSION TUBE CONSISTS OF IDLING JET THAT THE EMULSION TUBE CONSISTS OF IDLING JET THAT REGULATE AMOUNT OF FUEL DRAWN FROM MAIN REGULATE AMOUNT OF FUEL DRAWN FROM MAIN DISCHARGE SYSTEM.DISCHARGE SYSTEM.

TYPICAL IDLING SYSTEMTYPICAL IDLING SYSTEM

IDLE AIR BLEED AIDS IN EMULSIFYING THE FUEL.IDLE AIR BLEED AIDS IN EMULSIFYING THE FUEL.THROTTLE CLOSED, VENTURI IS ESTABLISHED NEAR THROTTLE CLOSED, VENTURI IS ESTABLISHED NEAR THE DISCHARGE PORTS CREATING LOW PRESSURE, THE DISCHARGE PORTS CREATING LOW PRESSURE, DRAWS FUEL FROM DISCHARGED PORTS AND INTO DRAWS FUEL FROM DISCHARGED PORTS AND INTO AIRSTREAM.AIRSTREAM.THUMB SCREW TYPE ADJUSTABLE NEEDLE VALVE THUMB SCREW TYPE ADJUSTABLE NEEDLE VALVE CONTROL THE AMOUNT OF FUEL DISCHARGE INTO THE CONTROL THE AMOUNT OF FUEL DISCHARGE INTO THE AIRSTREAM.AIRSTREAM.NEEDLE VALVE SCREWED IN REDUCING FUEL NEEDLE VALVE SCREWED IN REDUCING FUEL DISCHARGE AND MIXTURE BECOME LEANER.DISCHARGE AND MIXTURE BECOME LEANER.SCREWED OUT RICHEN THE IDLE MIXTURE.SCREWED OUT RICHEN THE IDLE MIXTURE.GENERALLY, MIXTURE FOR IDLING SYSTEM IS RICH FOR GENERALLY, MIXTURE FOR IDLING SYSTEM IS RICH FOR COOLING PURPOSES.COOLING PURPOSES.IN MULTIPLE PORT IDLE SYSTEM, MORE PORTS WILL IN MULTIPLE PORT IDLE SYSTEM, MORE PORTS WILL EXPOSED AS THROTTLE VALVE MOVES TO ALLOW EXPOSED AS THROTTLE VALVE MOVES TO ALLOW MORE FUEL FLOW.MORE FUEL FLOW.PROVIDE SMOOTH TRANSITION FROM IDLE TO HIGHER PROVIDE SMOOTH TRANSITION FROM IDLE TO HIGHER POWER SETTING.POWER SETTING.POSITION OF THROTTLE IS IMPORTANT DURING POSITION OF THROTTLE IS IMPORTANT DURING STARTING TO PREVENT OVER RICH MIXTURESTARTING TO PREVENT OVER RICH MIXTURE

IDLING SYSTEM IDLING SYSTEM cont.cont.

MIXTURE CONTROLMIXTURE CONTROL

REGULATE THE RATIO OF FUEL/AIR REGULATE THE RATIO OF FUEL/AIR MIXTURE TO THE ENGINE AND ALLOW MIXTURE TO THE ENGINE AND ALLOW ENGINE TO OPERATE EFFICIENTLY AT ENGINE TO OPERATE EFFICIENTLY AT VARIOUS ALTITUDE AND CONDITION.VARIOUS ALTITUDE AND CONDITION.TWO COMMON METHODS USED:TWO COMMON METHODS USED:– VARIABLE ORIFICE.VARIABLE ORIFICE.– BACK SUCTION.BACK SUCTION.

VARIABLE ORIFICE VARIABLE ORIFICE - FLOAT CHAMBER IS VENTED - FLOAT CHAMBER IS VENTED TO ATMOSPHERE AND A VALVE IS INSTALLED IN TO ATMOSPHERE AND A VALVE IS INSTALLED IN THE FLOAT CHAMBER TO CONTROL THE SIZE OF THE FLOAT CHAMBER TO CONTROL THE SIZE OF THE PASSAGE BETWEEN THE FLOAT CHAMBER THE PASSAGE BETWEEN THE FLOAT CHAMBER TO THE METERING JET.TO THE METERING JET.SOME CARBURETOR USE NEEDLE VALVE TO SOME CARBURETOR USE NEEDLE VALVE TO CONTROL FUEL FLOW.CONTROL FUEL FLOW.SOME USE A STEP-CUT ROTARY VALVE, SOME USE A STEP-CUT ROTARY VALVE, INSTALLED IN SERIES WITH THE MAIN FUEL INSTALLED IN SERIES WITH THE MAIN FUEL METERING JET.METERING JET.MIXTURE VALVE IN IDLE-CUTOFF, NO FUEL FLOWS MIXTURE VALVE IN IDLE-CUTOFF, NO FUEL FLOWS TO THE MAIN METERING JET.TO THE MAIN METERING JET.FULLY OPEN, FUEL FLOWS RESTRICTED BY MAIN FULLY OPEN, FUEL FLOWS RESTRICTED BY MAIN METERING JET. METERING JET. INTERMEDIATE POSITION THE AMOUNT OF FUEL INTERMEDIATE POSITION THE AMOUNT OF FUEL FLOW DETERMINE BY SIZE OF THE MIXTURE FLOW DETERMINE BY SIZE OF THE MIXTURE VALVE.VALVE.

MIXTURE CONTROL MIXTURE CONTROL cont.cont.

TYPICAL VARIABLE ORIFICE TYPICAL VARIABLE ORIFICE MIXTURE CONTROLMIXTURE CONTROL

BACK SUCTION MIXTURE CONTROL BACK SUCTION MIXTURE CONTROL - LOW - LOW PRESSURE AIR IS USED TO CONTROL THE PRESSURE AIR IS USED TO CONTROL THE PRESSURE DIFFERENTIAL BETWEEN THE PRESSURE DIFFERENTIAL BETWEEN THE VENTURI AND THE FLOAT CHAMBER.VENTURI AND THE FLOAT CHAMBER.LOW PRESSURE AIR FROM VENTURI, LOW PRESSURE AIR FROM VENTURI, ROUTED THROUGH MIXTURE VALVE INTO ROUTED THROUGH MIXTURE VALVE INTO FLOAT CHAMBER.FLOAT CHAMBER.FLOAT CHAMBER IS VENTED TO FLOAT CHAMBER IS VENTED TO ATMOSPHERE AND THE LOW PRESSURE ATMOSPHERE AND THE LOW PRESSURE AREA NEAR VENTURI.AREA NEAR VENTURI.MIXTURE CONTROL IN ‘RICH’ POSITION, MIXTURE CONTROL IN ‘RICH’ POSITION, VENT VALVE FULLY OPEN TO VENT VALVE FULLY OPEN TO ATMOSPHERE, CREATING LARGE ATMOSPHERE, CREATING LARGE PRESSURE DIFFERENTIAL AND MAXIMUM PRESSURE DIFFERENTIAL AND MAXIMUM FUEL FLOW TO DISCHARGE NOZZLE.FUEL FLOW TO DISCHARGE NOZZLE.


‘‘IDLE-CUT OFF POSITION’ CHAMBER IDLE-CUT OFF POSITION’ CHAMBER VENTED TO LOW PRESSURE AIR, VENTED TO LOW PRESSURE AIR, ELIMINATES PRESSURE DIFFERENTIAL ELIMINATES PRESSURE DIFFERENTIAL AND STOP FUEL FLOW.AND STOP FUEL FLOW.INTERMEDIATE POSITION FLOAT CHAMBER INTERMEDIATE POSITION FLOAT CHAMBER VENTED TO COMBINATION OF VENTED TO COMBINATION OF ATMOSPHERE AIR AND VENTURI AIR.ATMOSPHERE AIR AND VENTURI AIR.THE TWO PRESSURE DICTATES THE THE TWO PRESSURE DICTATES THE PRESSURE DIFFERENTIAL BETWEEN THE PRESSURE DIFFERENTIAL BETWEEN THE FLOAT CHAMBER AND DISCHARGE FLOAT CHAMBER AND DISCHARGE NOZZLE, CONTROL THE AMOUNT OF FUEL NOZZLE, CONTROL THE AMOUNT OF FUEL DISCHARGED. DISCHARGED.


TYPICAL BACK-SUCTION TYPICAL BACK-SUCTION MIXTURE CONTROLMIXTURE CONTROL

AUTOMATIC MIXTURE CONTROL (AMC).AUTOMATIC MIXTURE CONTROL (AMC).

AS A/C ASCENDS, MIXTURE IS AS A/C ASCENDS, MIXTURE IS AUTOMATICALLY LEANED TO PROVIDE AUTOMATICALLY LEANED TO PROVIDE OPTIMUM FUEL/AIR RATIO.OPTIMUM FUEL/AIR RATIO.AS A/C DESCENDS MIXTURE CONTROL AS A/C DESCENDS MIXTURE CONTROL ENRICHENS THE MIXTURE.ENRICHENS THE MIXTURE.AMC UTILIZES A SEALED BELLOW AMC UTILIZES A SEALED BELLOW POSITION EITHER A BACK SUCTION OR POSITION EITHER A BACK SUCTION OR VARIABLE ORIFICE TYPE MIXTURE VARIABLE ORIFICE TYPE MIXTURE CONTROL THROUGH AN ACTUATOR.CONTROL THROUGH AN ACTUATOR.A/C CLIMB, BELLOW EXPANDS AND A/C CLIMB, BELLOW EXPANDS AND REDUCES THE AMOUNT OF FUEL FLOW TO REDUCES THE AMOUNT OF FUEL FLOW TO THE DISCHARGED NOZZLE, LEANING THE THE DISCHARGED NOZZLE, LEANING THE MIXTURE.MIXTURE.

AUTOMATIC MIXTURE CONTROL (AMC) AUTOMATIC MIXTURE CONTROL (AMC) CONT.CONT.

A/C DESCENDS, BELLOW CONTRACT AND A/C DESCENDS, BELLOW CONTRACT AND ENRICHEN THE MIXTURE.ENRICHEN THE MIXTURE.MALFUNCTIONS OF AMC:MALFUNCTIONS OF AMC:A/C EXPERIENCES RISING IN CHT DURING A/C EXPERIENCES RISING IN CHT DURING DESCEND, MIXTURE BECOME LEANER, DESCEND, MIXTURE BECOME LEANER, CONTROL ACTUATOR (BELLOW) STUCK IN CONTROL ACTUATOR (BELLOW) STUCK IN EXTENDED POSITION.EXTENDED POSITION.ENGINE NOT PRODUCE FULL POWER AT ENGINE NOT PRODUCE FULL POWER AT ALTITUDE, CONTROL ACTUATOR (BELLOW) ALTITUDE, CONTROL ACTUATOR (BELLOW) STUCK IN RETRACTED POSITION OR STUCK IN RETRACTED POSITION OR PUNCTURED – PROVIDE RICH MIXTURE.PUNCTURED – PROVIDE RICH MIXTURE.

SEALED SEALED BELLOWS OF AN BELLOWS OF AN AMCAMC

NOTENOTE

AMC IN AMC IN OPERATIOOPERATIONN

ACCELERATION SYSTEMACCELERATION SYSTEM WHEN THROTTLE IS RAPIDLY OPENED, WHEN THROTTLE IS RAPIDLY OPENED,

AIRFLOW INCREASES BEFORE DISCHARGED AIRFLOW INCREASES BEFORE DISCHARGED NOZZLE HAS THE TIME TO INCREASE THE NOZZLE HAS THE TIME TO INCREASE THE AMOUNT OF FUEL FLOW.AMOUNT OF FUEL FLOW.

DELAY RESPOND CREATES MOMENTARY DELAY RESPOND CREATES MOMENTARY LEANING OF FUEL/AIR MIXTURE CAUSE LEANING OF FUEL/AIR MIXTURE CAUSE ENGINE TO STAGGER BEFORE ENGINE TO STAGGER BEFORE ACCELERATING.ACCELERATING.

TO PREVENT THIS, CARBURETOR PROVIDES TO PREVENT THIS, CARBURETOR PROVIDES AN IMMEDIATE BUT BRIEF INCREASE IN FUEL AN IMMEDIATE BUT BRIEF INCREASE IN FUEL FLOW IN THE THROAT OF THE CARBURETOR FLOW IN THE THROAT OF THE CARBURETOR TO ENRICHEN THE MIXTURE.TO ENRICHEN THE MIXTURE.

WITH EXTRA FUEL, ENGINE CAN ACCELERATE WITH EXTRA FUEL, ENGINE CAN ACCELERATE SMOOTHLY AND QUICKLY UNTIL DISCHARGED SMOOTHLY AND QUICKLY UNTIL DISCHARGED NOZZLE CAN DELIVER FUEL AT A RATE NOZZLE CAN DELIVER FUEL AT A RATE PROPORTIONAL TO THE AIRFLOW RATE.PROPORTIONAL TO THE AIRFLOW RATE.

ACCELERATION WELL.ACCELERATION WELL. TWO SYSTEMS MOST COMMONLY USED:TWO SYSTEMS MOST COMMONLY USED:

ACCELERATION WELL.ACCELERATION WELL.ACCELERATION PUMP. ACCELERATION PUMP.

LOCATED IN THE MAIN DISCHARGED NOZZLE.LOCATED IN THE MAIN DISCHARGED NOZZLE. AN ENLARGED ANNULAR CHAMBER AN ENLARGED ANNULAR CHAMBER

SURROUNDS THE MAIN DISCHARGED NOZZLE SURROUNDS THE MAIN DISCHARGED NOZZLE AT THE MAIN AIR BLEED JUNCTION.AT THE MAIN AIR BLEED JUNCTION.

ENGINE RUNNING, FUEL IS STORED IN THE ENGINE RUNNING, FUEL IS STORED IN THE ACCELERATION WELL.ACCELERATION WELL.

THROTTLE RAPIDLY ADVANCED, THE FUEL IN THROTTLE RAPIDLY ADVANCED, THE FUEL IN ACCELERATION WELL IS DRAWN OUT ACCELERATION WELL IS DRAWN OUT THROUGH THE DISCHARGE NOZZLE TO THROUGH THE DISCHARGE NOZZLE TO PROVIDE RICH MIXTURE. PROVIDE RICH MIXTURE.

TYPICAL ACCELERATION WELLTYPICAL ACCELERATION WELL

ACCELERATION PUMPACCELERATION PUMP• CONSIST OF A LEATHER PACKING HELD CONSIST OF A LEATHER PACKING HELD

AGAINST THE WALL OF A PUMP CHAMBER BY AGAINST THE WALL OF A PUMP CHAMBER BY COILED SPRING.COILED SPRING.

• PUMP CONNECTED TO THE THROTTLE VALVE PUMP CONNECTED TO THE THROTTLE VALVE SHAFT ACTUATED BY THE THROTTLE SHAFT ACTUATED BY THE THROTTLE LINKAGE.LINKAGE.

• WHEN THROTTLE CLOSED THE WHEN THROTTLE CLOSED THE ACCELERATOR PUMP MOVES UPWARD IN THE ACCELERATOR PUMP MOVES UPWARD IN THE CHAMBER CAUSES FUEL TO FILL THE CHAMBER CAUSES FUEL TO FILL THE CHAMBER FROM FLOAT BOWL THROUGH A CHAMBER FROM FLOAT BOWL THROUGH A PUMP INLET CHECK VALVE.PUMP INLET CHECK VALVE.

• WHEN THROTTLE OPEN QUICKLY, PISTON WHEN THROTTLE OPEN QUICKLY, PISTON MOVES DOWN AND FORCES THE STORED MOVES DOWN AND FORCES THE STORED FUEL PAST A DISCHARGE CHECK VALVE AND FUEL PAST A DISCHARGE CHECK VALVE AND THROUGH A SEPARATE DISCHARGE NOZZLE THROUGH A SEPARATE DISCHARGE NOZZLE INTO THE AIRSTREAM.INTO THE AIRSTREAM.

TYPICAL ACCELERATOR PUMPTYPICAL ACCELERATOR PUMP

• THE DISCHARGE CHECK VALVE AND THE DISCHARGE CHECK VALVE AND NOZZLE ARE MUCH SMALLER THAN THE NOZZLE ARE MUCH SMALLER THAN THE ACCELERATOR PUMP PISTON.ACCELERATOR PUMP PISTON.

• THE SPEED OF PUMPING THE FUEL MUST THE SPEED OF PUMPING THE FUEL MUST BE LIMITED BY INSTALLING THE PISTON ON BE LIMITED BY INSTALLING THE PISTON ON A SPRING LOADED TELESCOPING SHAFT A SPRING LOADED TELESCOPING SHAFT WHICH CONTRACT WHEN THROTTLE WHICH CONTRACT WHEN THROTTLE VALVE OPEN RAPIDLY AND ALLOW VALVE OPEN RAPIDLY AND ALLOW THROTTLE VALVE TO OPEN FULLY.THROTTLE VALVE TO OPEN FULLY.

• SPRING ON THE TELESCOPING SHAFT SPRING ON THE TELESCOPING SHAFT CONTINUES TO FORCE PISTON CONTINUES TO FORCE PISTON DOWNWARD TO PUMP FUEL AT RATE THE DOWNWARD TO PUMP FUEL AT RATE THE DISCHARGE NOZZLE CAN HANDLE DISCHARGE NOZZLE CAN HANDLE

ACCELERATION PUMP ACCELERATION PUMP cont.cont.

POWER ENRICHMENT / POWER ENRICHMENT / ECONOMIZER SYSTEM.ECONOMIZER SYSTEM.

PROVIDE RICH MIXTURE AT HIGH POWER PROVIDE RICH MIXTURE AT HIGH POWER SETTING.SETTING.EXCESS FUEL IN THE MIXTURE HELPS TO EXCESS FUEL IN THE MIXTURE HELPS TO COOL THE ENGINE CYLINDER.COOL THE ENGINE CYLINDER.FUNCTION AT THROTTLE SETTING ABOVE FUNCTION AT THROTTLE SETTING ABOVE CRUISING POWER.CRUISING POWER.NORMAL CRUISE OPERATION AT HIGH POWER NORMAL CRUISE OPERATION AT HIGH POWER SETTING PERMIT THE USE OF LEANER SETTING PERMIT THE USE OF LEANER MIXTURE.MIXTURE.POWER ENRICHMENT ALSO REFERRED TO AS POWER ENRICHMENT ALSO REFERRED TO AS ECONOMIZER SYSTEM.ECONOMIZER SYSTEM.TWO TYPES COMMONLY USE ARE NEEDLE TWO TYPES COMMONLY USE ARE NEEDLE TYPE AND AIR BLEED TYPETYPE AND AIR BLEED TYPE

NEEDLE TYPENEEDLE TYPE

ENRICHMENT METERING JET OPERATES ENRICHMENT METERING JET OPERATES PARALLEL WITH MAIN METERING JET.PARALLEL WITH MAIN METERING JET.OPERATING BELOW FULL THROTTLE, A OPERATING BELOW FULL THROTTLE, A SPRING HOLDS THE NEEDLE VALVE ON ITS SPRING HOLDS THE NEEDLE VALVE ON ITS SEAT PREVENTING FUEL FROM FLOWING SEAT PREVENTING FUEL FROM FLOWING THROUGH THE ECONOMIZER JET.THROUGH THE ECONOMIZER JET.THROTTLE WIDE OPEN, A LINKAGE LIFTS THROTTLE WIDE OPEN, A LINKAGE LIFTS THE ECONOMIZER NEEDLE VALVE OFF ITS THE ECONOMIZER NEEDLE VALVE OFF ITS SEAT TO ALLOW FUEL FLOW THROUGH SEAT TO ALLOW FUEL FLOW THROUGH THE ECONOMIZER JET AND OUT TO THE THE ECONOMIZER JET AND OUT TO THE DISCHARGED NOZZLE. DISCHARGED NOZZLE.

NEEDLE TYPE ECONOMIZERNEEDLE TYPE ECONOMIZER

AIR BLEED TYPEAIR BLEED TYPEA NEEDLE VALVE AND SEAT INSTALLED AT A NEEDLE VALVE AND SEAT INSTALLED AT THE AIR BLEED ENTRANCE.THE AIR BLEED ENTRANCE.WHEN ENGINE OPERATING AT CRUISING WHEN ENGINE OPERATING AT CRUISING SPEED, A SPRING HOLDS THE NEEDLE SPEED, A SPRING HOLDS THE NEEDLE VALVE OFF ITS SEAT AND FULL EFFECT OF VALVE OFF ITS SEAT AND FULL EFFECT OF THE AIR BLEED IS REALIZED AT THE THE AIR BLEED IS REALIZED AT THE DISCHARGED NOZZLE.DISCHARGED NOZZLE.WHEN THROTTLE IS FULLY OPEN, WHEN THROTTLE IS FULLY OPEN, OPERATING LEVER ATTACHED TO THE OPERATING LEVER ATTACHED TO THE THROTTLE SHAFT PRESSES AGAINST THE THROTTLE SHAFT PRESSES AGAINST THE NEEDLE VALVE RESTRICTING THE AIR NEEDLE VALVE RESTRICTING THE AIR BLEED.BLEED.THIS DECREASED AIR BLEED AND FUEL/AIR THIS DECREASED AIR BLEED AND FUEL/AIR MIXTURE BECOMES RICHER. MIXTURE BECOMES RICHER.

AIR BLEED TYPE AIR BLEED TYPE ECONOMIZERECONOMIZER

CARBURETOR LIMITATIONSCARBURETOR LIMITATIONS FLOAT-TYPE CARBURETOR UTILIZE LOW FLOAT-TYPE CARBURETOR UTILIZE LOW

OPERATING PRESSURE RESULT IN OPERATING PRESSURE RESULT IN INCOMPLETE VAPORIZATION AND INADEQUATE INCOMPLETE VAPORIZATION AND INADEQUATE FUEL FLOW FROM THE DISCHARGED NOZZLE.FUEL FLOW FROM THE DISCHARGED NOZZLE.

FLOAT DESIGN DOES NOT RESPOND WELL TO FLOAT DESIGN DOES NOT RESPOND WELL TO SUDDEN A/C MANEUVERS AND UNUSUAL A/C SUDDEN A/C MANEUVERS AND UNUSUAL A/C ALTITUDE.ALTITUDE.

TENDENCY TO ACCUMULATE ICE.TENDENCY TO ACCUMULATE ICE. CARBURETOR ICING OCCURS WHEN WATER CARBURETOR ICING OCCURS WHEN WATER

FREEZES IN CARBURETOR VENTURI AND FREEZES IN CARBURETOR VENTURI AND RESTRICT THE AIRFLOW TO THE ENGINE.RESTRICT THE AIRFLOW TO THE ENGINE.

ENGINE MAY RUN ROUGH, LOSE POWER AND ENGINE MAY RUN ROUGH, LOSE POWER AND EVEN QUIT IN FLIGHT.EVEN QUIT IN FLIGHT.

CARBURETOR ICING IS CATEGORIZE INTO FUEL CARBURETOR ICING IS CATEGORIZE INTO FUEL EVAPORATION ICE AND THROTTLE ICE.EVAPORATION ICE AND THROTTLE ICE.

CARBURETOR LIMITATIONS CARBURETOR LIMITATIONS CONT.CONT.

FUEL EVAPORATION ICE FUEL EVAPORATION ICE RESULT FROM RESULT FROM TEMPERATURE DROP OCCURS WHEN FUEL TEMPERATURE DROP OCCURS WHEN FUEL VAPORIZED IN THE VENTURI.VAPORIZED IN THE VENTURI.

DISCHARGED FUEL INTO VENTURI TURN VAPOR DISCHARGED FUEL INTO VENTURI TURN VAPOR AND ABSORBS HEAT FROM SURROUNDING AIR.AND ABSORBS HEAT FROM SURROUNDING AIR.

EVAPORATION CAUSE AIR TEMPERATURE IN THE EVAPORATION CAUSE AIR TEMPERATURE IN THE VENTURI TO DROP 30VENTURI TO DROP 30°° F OR MORE.F OR MORE.

LOSS OF HEAT ENOUGH TO CAUSE THE MOISTURE LOSS OF HEAT ENOUGH TO CAUSE THE MOISTURE IN THE AIR TO CONDENSE AND FREEZE.IN THE AIR TO CONDENSE AND FREEZE.

CARBURETOR IS THE FIRST AREA IN A/C TO CARBURETOR IS THE FIRST AREA IN A/C TO ACCUMULATE ICE DURING FLIGHT.ACCUMULATE ICE DURING FLIGHT.

CARBURETOR ICE CAN OCCUR AT AMBIENT AIR CARBURETOR ICE CAN OCCUR AT AMBIENT AIR TEMPERATURE UP TO 70TEMPERATURE UP TO 70°°F WITH RELATIVE F WITH RELATIVE HUMIDITY AS LOW AS 50%.HUMIDITY AS LOW AS 50%.

OPTIMUM CONDITION FOR CARBURETOR ICE EXIST OPTIMUM CONDITION FOR CARBURETOR ICE EXIST WHEN OUTSIDE AIR TEMPERATURE BETWEEN 30WHEN OUTSIDE AIR TEMPERATURE BETWEEN 30°°F F TO 40TO 40°°F WITH RELATIVE HUMIDITY ABOVE 60%.F WITH RELATIVE HUMIDITY ABOVE 60%.

THROTTLE ICING THROTTLE ICING DESCRIBE ICE FORMS ON THE DESCRIBE ICE FORMS ON THE REAR SIDE OF THE THROTTLE VALVE WHEN IT IS REAR SIDE OF THE THROTTLE VALVE WHEN IT IS PARTIALLY CLOSED.PARTIALLY CLOSED.

AIR FLOWS ACROSS AND AROUND THE THROTTLE AIR FLOWS ACROSS AND AROUND THE THROTTLE VALVE, A LOW PRESSURE AREA IS CREATED ON VALVE, A LOW PRESSURE AREA IS CREATED ON THE DOWNSTREAM SIDE.THE DOWNSTREAM SIDE.

THE COOLING EFFECT ON THE FUEL/AIR MIXTURE THE COOLING EFFECT ON THE FUEL/AIR MIXTURE CAUSE MOISTURE TO ACCUMULATE AND FREEZE CAUSE MOISTURE TO ACCUMULATE AND FREEZE ON THE BACKSIDE OF THE THROTTLE VALVE.ON THE BACKSIDE OF THE THROTTLE VALVE.

SINCE THROTTLE ICE OCCURS WITH THROTTLE SINCE THROTTLE ICE OCCURS WITH THROTTLE VALVE PARTIALLY CLOSED, SMALL AMOUNT OF VALVE PARTIALLY CLOSED, SMALL AMOUNT OF ICE CAN CAUSE REDUCTION IN AIR FLOW AND ICE CAN CAUSE REDUCTION IN AIR FLOW AND LOSE OF ENGINE POWER.LOSE OF ENGINE POWER.

LARGE ACCUMULATION OF ICE CAN JAM THE LARGE ACCUMULATION OF ICE CAN JAM THE THROTTLE.THROTTLE.

THROTTLE ICE SELDOM OCCURS AT THROTTLE ICE SELDOM OCCURS AT TEMPERATURE ABOVE 38TEMPERATURE ABOVE 38°° F. F.

CARBURETOR LIMITATIONS CARBURETOR LIMITATIONS CONT.CONT.

FLOAT-TYPE CARBURETOR FLOAT-TYPE CARBURETOR MAINTENANCEMAINTENANCE

BASIC MAINTENANCE DEPEND ON YOUR BASIC MAINTENANCE DEPEND ON YOUR LEVEL OF PROFICIENCY, AVAILABILITY OF LEVEL OF PROFICIENCY, AVAILABILITY OF SPARE PARTS AND EQUIPMENTS.SPARE PARTS AND EQUIPMENTS.

IN-SITU, PERIODIC CHECKING OF ALL IN-SITU, PERIODIC CHECKING OF ALL CONTROL LINKAGES FOR FREEDOM OF CONTROL LINKAGES FOR FREEDOM OF MOVEMENT AT FULL RANGE.MOVEMENT AT FULL RANGE.

EXAMINE FUEL LINES AND AIR HOSES FOR EXAMINE FUEL LINES AND AIR HOSES FOR KINKS, DISTORTION OR INDICATION OF KINKS, DISTORTION OR INDICATION OF LEAKAGE.LEAKAGE.

VERIFY THE SECURITY OF CARBURETOR VERIFY THE SECURITY OF CARBURETOR MOUNTING FLANGE AND INSPECT FOR MOUNTING FLANGE AND INSPECT FOR SIGN OF CRACK OR LEAK.SIGN OF CRACK OR LEAK.

MAINTENANCEMAINTENANCE cont. cont.

LEAK BETWEEN CARBURETOR BODY AND LEAK BETWEEN CARBURETOR BODY AND ENGINE MOUNTING FLANGE ALLOWS ENGINE MOUNTING FLANGE ALLOWS ADDITIONAL AIR INTO THE FUEL / AIR ADDITIONAL AIR INTO THE FUEL / AIR MIXTURE, LEANING THE MIXTURE CAUSING MIXTURE, LEANING THE MIXTURE CAUSING ENGINE TO IDLE ROUGH AND PRODUCE ENGINE TO IDLE ROUGH AND PRODUCE LESS THAN FULL POWER.LESS THAN FULL POWER.

IF LEAK IS SEVERE ENOUGH, COULD LEAN IF LEAK IS SEVERE ENOUGH, COULD LEAN MIXTURE ENOUGH TO CAUSE DETONATION MIXTURE ENOUGH TO CAUSE DETONATION AND ENGINE DAMAGE.AND ENGINE DAMAGE.

ADDITIONAL MAINTENANCE:ADDITIONAL MAINTENANCE:CHECK MAIN FUEL FILTER AND CHECK MAIN FUEL FILTER AND

CARBURETOR STRAINER REGULARLY.CARBURETOR STRAINER REGULARLY.VERIFY ALL SAFETY WIRE AND COTTER VERIFY ALL SAFETY WIRE AND COTTER

PIN ARE IN PLACE AND SECURE.PIN ARE IN PLACE AND SECURE.

ON AUTOMATIC MIXTURE CONTROL, ON AUTOMATIC MIXTURE CONTROL, ACCELERATOR PUMP OR ECONOMIZER, ACCELERATOR PUMP OR ECONOMIZER, PERIODICALLY CLEAN ALL LINKAGES PERIODICALLY CLEAN ALL LINKAGES AND MOVING PARTS AND OIL, IF AND MOVING PARTS AND OIL, IF RECOMMENDED.RECOMMENDED.

THOUGH IS NOT PART OF A THOUGH IS NOT PART OF A CARBURETOR, AIR FILTER SHOULD CARBURETOR, AIR FILTER SHOULD ALSO BE CHECKED FOR SECURITY, ALSO BE CHECKED FOR SECURITY, CLEANLINESS, AND POSSIBLE AIR LEAK.CLEANLINESS, AND POSSIBLE AIR LEAK.

HEAT VALVE ALSO CHECK FOR PROPER HEAT VALVE ALSO CHECK FOR PROPER TRAVEL (RIGGING) AND FOR AIR LEAKS.TRAVEL (RIGGING) AND FOR AIR LEAKS.

APPLICATION OF HEAT DECREASE APPLICATION OF HEAT DECREASE DENSITY OF AIR WHICH WILL DECREASE DENSITY OF AIR WHICH WILL DECREASE POWER OUTPUT. POWER OUTPUT.


IDLE MIXTURE ADJUSTMENTS IDLE MIXTURE ADJUSTMENTS CORRECT IDLE MIXTURE ADJUSTMENT, RESULT IN CORRECT IDLE MIXTURE ADJUSTMENT, RESULT IN ENGINE IDLING SMOOTHLY AND SPARK PLUG ENGINE IDLING SMOOTHLY AND SPARK PLUG FOULING KEPT TO MINIMUM.FOULING KEPT TO MINIMUM.IDLE MIXTURE, CONTROL BY A NEEDLE VALVE IDLE MIXTURE, CONTROL BY A NEEDLE VALVE WITH A SCREW HEAD OR KNURLED KNOB, SPRING WITH A SCREW HEAD OR KNURLED KNOB, SPRING LOADED TO MAINTAIN A SETTING.LOADED TO MAINTAIN A SETTING.CHECK IDLE MIXTURE BY RUNNING THE ENGINE CHECK IDLE MIXTURE BY RUNNING THE ENGINE UNTIL THE CHT RISES TO A NORMAL VALUE.UNTIL THE CHT RISES TO A NORMAL VALUE.ONCE ENGINE WARM-UP, RETARD THE MIXTURE ONCE ENGINE WARM-UP, RETARD THE MIXTURE TOWARD IDLE–CUTOFF POSITION AND OBSERVE TOWARD IDLE–CUTOFF POSITION AND OBSERVE THE TACHOMETER.THE TACHOMETER.IF MIXTURE IS ADJUSTED PROPERLY ENGINE RPM IF MIXTURE IS ADJUSTED PROPERLY ENGINE RPM WILL INCREASE SLIGHTLY, BETWEEN 25 AND 50 WILL INCREASE SLIGHTLY, BETWEEN 25 AND 50 RPM, BEFORE IT DROPS OFF RAPIDLY.RPM, BEFORE IT DROPS OFF RAPIDLY.


TYPICAL IDLE MIXTURE TYPICAL IDLE MIXTURE CONTROLCONTROL

AN IMMEDIATE RPM DECREASE WITH NO AN IMMEDIATE RPM DECREASE WITH NO MOMENTARY INCREASE INDICATE IDLE MIXTURE IS MOMENTARY INCREASE INDICATE IDLE MIXTURE IS TOO LEAN.TOO LEAN.A MOMENTARY INCREASE MORE THAN 25 RPM A MOMENTARY INCREASE MORE THAN 25 RPM INDICATE A RICH IDLE MIXTURE.INDICATE A RICH IDLE MIXTURE.IF EQUIPPED WITH MANIFOLD PRESSURE GAUGE, IF EQUIPPED WITH MANIFOLD PRESSURE GAUGE, MANIFOLD PRESSURE DECREASING JUST BEFORE MANIFOLD PRESSURE DECREASING JUST BEFORE IT INCREASES WHEN ENGINE CEASES TO FIRE. THE IT INCREASES WHEN ENGINE CEASES TO FIRE. THE AMOUNT OF DROP IS ABOUT ¼ INCH. HG.AMOUNT OF DROP IS ABOUT ¼ INCH. HG.AFTER PROPER MIXTURE IS OBTAIN, CLEAR THE AFTER PROPER MIXTURE IS OBTAIN, CLEAR THE ENGINE BY RUNNING IT AT A HIGH RPM TO ENGINE BY RUNNING IT AT A HIGH RPM TO PREVENT SPARK FOULING. PREVENT SPARK FOULING. ONCE THE CURRENT RPM INDICATION OBTAINED, ONCE THE CURRENT RPM INDICATION OBTAINED, REPEAT THE IDLE MIXTURE CHECK WITH THE REPEAT THE IDLE MIXTURE CHECK WITH THE COCKPIT MIXTURE CONTROL SEVERAL TIME TO COCKPIT MIXTURE CONTROL SEVERAL TIME TO ENSURE A CONSISTENT RESPONSE.ENSURE A CONSISTENT RESPONSE.


IDLE SPEED ADJUSTMENTIDLE SPEED ADJUSTMENTADJUSTED AFTER ADJUSTING THE IDLE MIXTURE.ADJUSTED AFTER ADJUSTING THE IDLE MIXTURE.TYPICAL IDLE SPEEDS RANGE FROM 600 - 800 RPMTYPICAL IDLE SPEEDS RANGE FROM 600 - 800 RPMSPRING-LOADED ADJUSTMENT SCREW.SPRING-LOADED ADJUSTMENT SCREW.ENGINE SHOULD BE WARM BEFORE MAKING ANY ENGINE SHOULD BE WARM BEFORE MAKING ANY ADJUSTMENT.ADJUSTMENT.CHECK IGNITION SYSTEM FOR PROPER CHECK IGNITION SYSTEM FOR PROPER OPERATION.OPERATION.IF EVERYTHING IS OPERATING PROPERLY, OPEN IF EVERYTHING IS OPERATING PROPERLY, OPEN THE THROTTLE TO CLEAR THE ENGINE, THEN THE THROTTLE TO CLEAR THE ENGINE, THEN CLOSE THE THROTTLE AND ALLOW THE RPM TO CLOSE THE THROTTLE AND ALLOW THE RPM TO STABILIZE.STABILIZE.ADJUST IDLE SPEED SCREW AS NEEDED AND ADJUST IDLE SPEED SCREW AS NEEDED AND RECHECK THE IDLE SPEED.RECHECK THE IDLE SPEED.CLEAR THE ENGINE BY OPENING THE THROTTLE CLEAR THE ENGINE BY OPENING THE THROTTLE AFTER EACH ADJUSTMENT. AFTER EACH ADJUSTMENT.


IDLE SPEED IDLE SPEED ADJUSTMENT ADJUSTMENT

CARBURETOR OVERHAULCARBURETOR OVERHAUL COMMON PRACTICE TO OVERHAUL THE COMMON PRACTICE TO OVERHAUL THE

CARBURETOR AT THE TIME OF ENGINE OVERHAUL.CARBURETOR AT THE TIME OF ENGINE OVERHAUL. OVERHAUL PROCEDURE REQUIRED COMPLETE OVERHAUL PROCEDURE REQUIRED COMPLETE

TEARDOWN OF THE CARBURETOR AND A VISUAL TEARDOWN OF THE CARBURETOR AND A VISUAL INSPECTION OF ALL INTERNAL COMPONENTS.INSPECTION OF ALL INTERNAL COMPONENTS.

DIMENSIONAL CHECK MADE TO DETERMINED DIMENSIONAL CHECK MADE TO DETERMINED SERVICEABILITY OF EACH REUSABLE SERVICEABILITY OF EACH REUSABLE COMPONENTS.COMPONENTS.

TYPICALLY THE FOLLOWING PROCEDURES TYPICALLY THE FOLLOWING PROCEDURES APPLIES:APPLIES: DISASSEMBLYDISASSEMBLY CLEANINGCLEANING INSPECTION INSPECTION REASSEMBLY REASSEMBLY INSTALLATION INSTALLATION

CARBURETOR OVERHAULCARBURETOR OVERHAUL cont. cont.

DISASSEMBLY. DISASSEMBLY. SHOULD BE DONE ON A CLEAN WORK SHOULD BE DONE ON A CLEAN WORK

BENCH WHERE ALL PARTS CAN BE LAID BENCH WHERE ALL PARTS CAN BE LAID OUT SYSTEMATICALLY.OUT SYSTEMATICALLY.

DISASSEMBLE IN SEQUENCE AS DISASSEMBLE IN SEQUENCE AS INSTRUCTED IN THE OVERHAUL MANUAL INSTRUCTED IN THE OVERHAUL MANUAL TO PREVENT DAMAGE TO DELICATES TO PREVENT DAMAGE TO DELICATES PARTS.PARTS.

USE PROPER TOOLS TO PREVENT USE PROPER TOOLS TO PREVENT DAMAGE TO THE CARBURETOR.DAMAGE TO THE CARBURETOR.

WHEN SPECIAL TOOLS IS REQUIRED, WHEN SPECIAL TOOLS IS REQUIRED, OBTAIN IT RATHER THAN IMPROVISING OBTAIN IT RATHER THAN IMPROVISING TO PREVENT DAMAGE ESPECIALLY TO PREVENT DAMAGE ESPECIALLY BRONZE PARTS.BRONZE PARTS.

CLEANING.CLEANING. ONCE PRELIMINARY INSPECTION CARRIED ONCE PRELIMINARY INSPECTION CARRIED

OUT, CLEAN REUSABLE PARTS, USING OUT, CLEAN REUSABLE PARTS, USING RECOMMENDED CLEANING PROCEDURES RECOMMENDED CLEANING PROCEDURES AND SOLVENTS AS LISTED IN THE AND SOLVENTS AS LISTED IN THE OVERHAUL MANUAL.OVERHAUL MANUAL.

METAL PARTS CLEAN WITH APPROVED METAL PARTS CLEAN WITH APPROVED ‘‘STODDARD SOLVENT’ STODDARD SOLVENT’ TO REMOVE GREASE TO REMOVE GREASE AND OIL.AND OIL.

AFTER RINSING IN FRESH SOLVENT, ALL AFTER RINSING IN FRESH SOLVENT, ALL PART ARE AIR DRIED.PART ARE AIR DRIED.

DO NOT USE WIPING CLOTHS OR SHOP DO NOT USE WIPING CLOTHS OR SHOP RAGS, TO AVOID DEPOSIT OF LINT AND RAGS, TO AVOID DEPOSIT OF LINT AND THREAD THAT CAN OBSTRUCT METERING THREAD THAT CAN OBSTRUCT METERING JETS AND CAUSE CLOSE-FITTING-PARTS TO JETS AND CAUSE CLOSE-FITTING-PARTS TO BIND.BIND.


REMOVAL OF CARBON AND GUM DEPOSITS BY REMOVAL OF CARBON AND GUM DEPOSITS BY DECARBONIZING SOLUTION.DECARBONIZING SOLUTION.

TAKE NECESSARY PRECAUTIONS AND WEAR TAKE NECESSARY PRECAUTIONS AND WEAR PPE.PPE.

AFTER DECARBONIZED, RINSE IN HOT WATER, AFTER DECARBONIZED, RINSE IN HOT WATER, CLEAN AND DRY BY COMPRESSED AIR.CLEAN AND DRY BY COMPRESSED AIR.

GIVE SPECIAL ATTENTION TO INTERNAL GIVE SPECIAL ATTENTION TO INTERNAL PASSAGES, BLEEDS AND RECESSES WHEN PASSAGES, BLEEDS AND RECESSES WHEN RINSING & DRYING.RINSING & DRYING.

IF CARBON DEPOSIT REMAIN ON ALUMINUM IF CARBON DEPOSIT REMAIN ON ALUMINUM PARTS, REMOVE WITH NO. 600 WET SANDPAPER PARTS, REMOVE WITH NO. 600 WET SANDPAPER AND WATER.AND WATER.

CORROSION ON ALUMINUM PARTS REMOVE IT CORROSION ON ALUMINUM PARTS REMOVE IT WITH ALKALINE CLEANER OR RECOMMENDED WITH ALKALINE CLEANER OR RECOMMENDED AGENT.AGENT.


INSPECTION.INSPECTION. COMPLETE VISUAL INSPECTION FOR COMPLETE VISUAL INSPECTION FOR

SERVICIBILITY, FREE FROM CORROSION, SERVICIBILITY, FREE FROM CORROSION, DENT, BENT PARTS AND CROSSED THREADS.DENT, BENT PARTS AND CROSSED THREADS.

ENSURE ALL PASSAGES NOT BLOCKED – USE ENSURE ALL PASSAGES NOT BLOCKED – USE MAGNIFYING GLASS AND LIGHT.MAGNIFYING GLASS AND LIGHT.

DO NOT USE WIRE TO CLEAR HOLE.DO NOT USE WIRE TO CLEAR HOLE. ALL MOVING PARTS CHECK FOR FREE ALL MOVING PARTS CHECK FOR FREE

MOVEMENT.MOVEMENT. CHECK FLOAT FOR LEAK AND BUOYANCY BY CHECK FLOAT FOR LEAK AND BUOYANCY BY

IMMERSING IN THE HOT WATER (BRASS IMMERSING IN THE HOT WATER (BRASS FLOAT), IF LEAK, REPAIRED BY SOLDERING.FLOAT), IF LEAK, REPAIRED BY SOLDERING.

FOR COMPOSITE MATERIAL, IF LOSS OF FOR COMPOSITE MATERIAL, IF LOSS OF BUOYANCY, CHANGE.BUOYANCY, CHANGE.


NEEDLE VALVE AND SEAT, CHECK FOR WEAR, NEEDLE VALVE AND SEAT, CHECK FOR WEAR, GROOVES, SCRATCHES AND PITS.GROOVES, SCRATCHES AND PITS.

NEEDLE VALVE AND SEAT THAT DO NOT SEAT NEEDLE VALVE AND SEAT THAT DO NOT SEAT PROPERLY WILL CAUSE FUEL LEAK WHEN PROPERLY WILL CAUSE FUEL LEAK WHEN ENGINE IS SHUT DOWN.ENGINE IS SHUT DOWN.

REPLACE IF SHOW SIGN OF LEAK.REPLACE IF SHOW SIGN OF LEAK. FUEL LEVEL IN THE CARBURETOR IS BETWEEN FUEL LEVEL IN THE CARBURETOR IS BETWEEN

3/16 AND 1/8 INS. FROM THE TOP OF THE 3/16 AND 1/8 INS. FROM THE TOP OF THE DISCHARGE NOZZLE.DISCHARGE NOZZLE.

TOO LOW, GREATER PRESSURE DIFFERENTIAL TOO LOW, GREATER PRESSURE DIFFERENTIAL IS REQUIRE TO DRAW FUEL TO DISCHARGE IS REQUIRE TO DRAW FUEL TO DISCHARGE NOZZLENOZZLE

TOO HIGH, EXCESSIVE AMOUNT OF FUEL MAY TOO HIGH, EXCESSIVE AMOUNT OF FUEL MAY BE DRAWN INTO ENGINE.BE DRAWN INTO ENGINE.


FLOAT CLEARANCE IS MEASURED BY A FLOAT CLEARANCE IS MEASURED BY A RULER OR BY SLIPPING THE SHANK OF TWIST RULER OR BY SLIPPING THE SHANK OF TWIST DRILL OF PROPER SIZE BETWEEN THE DRILL OF PROPER SIZE BETWEEN THE GASKET AND THE TIP OF THE FLOAT WITH GASKET AND THE TIP OF THE FLOAT WITH THE THROTTLE BODY INVERTED.THE THROTTLE BODY INVERTED.

IF CORRECT CLEARANCE, DRILL SHOULD IF CORRECT CLEARANCE, DRILL SHOULD JUST TOUCH FLOAT WITHOUT CAUSING IT TO JUST TOUCH FLOAT WITHOUT CAUSING IT TO RISE.RISE.

IF INCORRECT, ADJUSTMENT TABS ARE IF INCORRECT, ADJUSTMENT TABS ARE PROVIDED TO CORRECT THE CLEARANCE AS PROVIDED TO CORRECT THE CLEARANCE AS NECESSARY.NECESSARY.


CHECKING FLOAT LEVELCHECKING FLOAT LEVEL

SHIMS OR ADJUSTMENT TAB ADD OR REMOVE FROM BELOW THE VALVE SEAT, AS NECESSARY

IN OTHER CARBURETORS, CHECK CARRIED IN OTHER CARBURETORS, CHECK CARRIED OUT WITH FLOAT MECHANISM FITTED, OUT WITH FLOAT MECHANISM FITTED, MOUNTED ON BENCH, PROPER FUEL MOUNTED ON BENCH, PROPER FUEL PRESSURE SUPPLY UNTIL BOWL FILLS AND PRESSURE SUPPLY UNTIL BOWL FILLS AND FLOATS CLOSE THE NEEDLE VALVE.FLOATS CLOSE THE NEEDLE VALVE.USE DEPTH GAUGE MEASURE DISTANCE USE DEPTH GAUGE MEASURE DISTANCE BETWEEN SURFACE OF FUEL AND PARTING BETWEEN SURFACE OF FUEL AND PARTING SURFACE OF BOWL.SURFACE OF BOWL.ENSURE MEASURE AWAY FROM WALL OF ENSURE MEASURE AWAY FROM WALL OF BOWL FOR ACCURATE MEASUREMENT TO BOWL FOR ACCURATE MEASUREMENT TO AVOID SURFACE TENSION OF FUEL.AVOID SURFACE TENSION OF FUEL.ADJUST IF NECESSARY BY INSERTING OR ADJUST IF NECESSARY BY INSERTING OR REMOVING SHIM FROM UNDERNEATH NEEDLE REMOVING SHIM FROM UNDERNEATH NEEDLE VALVE SEAT.VALVE SEAT.


SOME MANUFACTURER MAY REQUIRE YOU SOME MANUFACTURER MAY REQUIRE YOU TO CHECK TOTAL FLOAT TRAVELTO CHECK TOTAL FLOAT TRAVELWITH THROTTLE BODY IN UPRIGHT AND WITH THROTTLE BODY IN UPRIGHT AND FLOAT REST IN ITS LOWEST POSITION, FLOAT REST IN ITS LOWEST POSITION, MEASURE DISTANCE FROM MOUNTING MEASURE DISTANCE FROM MOUNTING FLANGE TO THE FLOAT TOP AND THIS IS FLANGE TO THE FLOAT TOP AND THIS IS REFERRED TO AS ‘FLOAT DROP’.REFERRED TO AS ‘FLOAT DROP’.IF INSUFFICIENT, ADJUST BY EITHER IF INSUFFICIENT, ADJUST BY EITHER BENDING THE ADJUSTMENT TAB OR FILING BENDING THE ADJUSTMENT TAB OR FILING THE FLOAT STOP. THE FLOAT STOP.

CARBURETOR OVERHAULCARBURETOR OVERHAUL cont.cont.

CHECKING FLOAT LEVELCHECKING FLOAT LEVEL

FLOAT TRAVEL IS FLOAT TRAVEL IS SUBTRACT FLOAT SUBTRACT FLOAT CLEARANCE FROM FLOAT CLEARANCE FROM FLOAT DROPDROP

NEXT CHECK THE SIDE CLEARANCE OF THE NEXT CHECK THE SIDE CLEARANCE OF THE FLOAT.FLOAT.CARRIED OUT WITH SPECIAL CUTAWAY FLOAT CARRIED OUT WITH SPECIAL CUTAWAY FLOAT BOWL FIXTURE.BOWL FIXTURE.MEASURED WITH DRILL ROD GAUGE OF MEASURED WITH DRILL ROD GAUGE OF SPECIFIED SIZE.SPECIFIED SIZE.GAUGE MUST PASS AROUND THE FLOAT GAUGE MUST PASS AROUND THE FLOAT WITHOUT BINDING.WITHOUT BINDING.ADJUSTMENT BY LOOSENING AND ADJUSTMENT BY LOOSENING AND REPOSITIONING THE FLOAT BRACKET.REPOSITIONING THE FLOAT BRACKET.ALL CHECK AND MEASUREMENT MUST FALL ALL CHECK AND MEASUREMENT MUST FALL WITHIN THE PERMISSIBLE LIMIT LISTED IN THE WITHIN THE PERMISSIBLE LIMIT LISTED IN THE OVERHAUL / MAINTENANCE MANUALOVERHAUL / MAINTENANCE MANUAL. .


TYPICAL SIDE CLEARANCE TYPICAL SIDE CLEARANCE CHECK OF FLOAT AND CHECK OF FLOAT AND

BOWLBOWL

ADDITIONALLY, VERIFY SIZE OF METERING JET ADDITIONALLY, VERIFY SIZE OF METERING JET THAT HAS NUMBER STAMP ON IT, WITH A NUMBER THAT HAS NUMBER STAMP ON IT, WITH A NUMBER DRILL SIZE.DRILL SIZE.

INSPECT DISCHARGE NOZZLE FOR INSPECT DISCHARGE NOZZLE FOR OBSTRUCTIONS, KINK AND BENT SECTIONS.OBSTRUCTIONS, KINK AND BENT SECTIONS.

FREE MOVEMENT OF THROTTLE VALVE.FREE MOVEMENT OF THROTTLE VALVE.

DIMENSIONAL CHECK ON THROTTLE VALVE SHAFT DIMENSIONAL CHECK ON THROTTLE VALVE SHAFT AND BUSHING FOR EXCESSIVE WEAR AND PLAY.AND BUSHING FOR EXCESSIVE WEAR AND PLAY.

CHECK BLEED PASSAGE FOR OBSTRUCTION.CHECK BLEED PASSAGE FOR OBSTRUCTION.

VENTURI AREA FOR CORROSION, SCORING AND VENTURI AREA FOR CORROSION, SCORING AND DEEP SCRATCHES.DEEP SCRATCHES.

BOOST VENTURI, IF FITTED, CHECK FOR BROKEN BOOST VENTURI, IF FITTED, CHECK FOR BROKEN OR BENT SUPPORT ARM.OR BENT SUPPORT ARM.


EXAMINE IDLE DISCHARGE JET AND SYSTEM EXAMINE IDLE DISCHARGE JET AND SYSTEM BLEED FOR OBSTRUCTION, NICKS, DENT AND BLEED FOR OBSTRUCTION, NICKS, DENT AND UPSET THAT COULD NARROW OPENING.UPSET THAT COULD NARROW OPENING.

MIXTURE CONTROL SHAFT MOVE FREELY AND MIXTURE CONTROL SHAFT MOVE FREELY AND DIMENSIONAL CHECK ALL MIXTURE PARTS WITHIN DIMENSIONAL CHECK ALL MIXTURE PARTS WITHIN LIMITS.LIMITS.

VISUALLY INSPECT AND VERIFY SECURITY OF VISUALLY INSPECT AND VERIFY SECURITY OF ACCELERATOR PUMP LINKAGE, MOVING PART ACCELERATOR PUMP LINKAGE, MOVING PART FOR PROPER TRAVELS AND FREEDOM OF FOR PROPER TRAVELS AND FREEDOM OF MOVEMENT AND ALL PARTS DIMENSIONALLY MOVEMENT AND ALL PARTS DIMENSIONALLY WITHIN LIMIT. WITHIN LIMIT.

POWER ENRICHMENT AND ECONOMIZER SYSTEM, POWER ENRICHMENT AND ECONOMIZER SYSTEM, VISUALLY INSPECT AND DIMENSIONALLY CHECK.VISUALLY INSPECT AND DIMENSIONALLY CHECK.


REASSEMBLY.REASSEMBLY. SEQUENCE OUTLINED IN THE OVERHAUL SEQUENCE OUTLINED IN THE OVERHAUL

MANUAL.MANUAL. USE SPECIAL TOOLS AS REQUIRED TO PREVENT USE SPECIAL TOOLS AS REQUIRED TO PREVENT

ACCIDENTAL DAMAGE TO COMPONENTS.ACCIDENTAL DAMAGE TO COMPONENTS. BEAR IN MIND THAT CARBURETOR BODIES ARE BEAR IN MIND THAT CARBURETOR BODIES ARE

MADE OF ALUMINUM ALLOY CASTING THAT CAN MADE OF ALUMINUM ALLOY CASTING THAT CAN EASILY BE DAMAGED.EASILY BE DAMAGED.

LUBRICATE THREADED FITTINGS, ENSURE LUBRICATE THREADED FITTINGS, ENSURE INSERT AT LEAST ONE THREAD BEFORE INSERT AT LEAST ONE THREAD BEFORE LUBRICANT IS APPLIED.LUBRICANT IS APPLIED.

THIS WILL PREVENT LUBRICANT FROM THIS WILL PREVENT LUBRICANT FROM ENTERING THE CARBURETOR AND PLUGGING ENTERING THE CARBURETOR AND PLUGGING THE JET AND SMALL PASSAGES.THE JET AND SMALL PASSAGES.


..

LUBRICATE ALL MOVING PARTS, TIGHTEN LUBRICATE ALL MOVING PARTS, TIGHTEN TO CORRECT TORQUE VALUE AND SAFETY TO CORRECT TORQUE VALUE AND SAFETY AS REQUIRED. AS REQUIRED. AFTER REASSEMBLE, FINAL CHECK OF AFTER REASSEMBLE, FINAL CHECK OF THE FUEL LEVEL IN THE FLOAT BOWL.THE FUEL LEVEL IN THE FLOAT BOWL.PROPER OPERATION OF THE FLOAT AND PROPER OPERATION OF THE FLOAT AND NEEDLE VALVE BE MADE.NEEDLE VALVE BE MADE.MEASURE THE DISTANCE FROM THE FUEL MEASURE THE DISTANCE FROM THE FUEL SURFACE TO THE PARTING SURFACE. SURFACE TO THE PARTING SURFACE.


FINAL CHECK OF FUEL FINAL CHECK OF FUEL LEVEL IN BOWLLEVEL IN BOWL

REINSTALL THE CARBURETOR TO THE REINSTALL THE CARBURETOR TO THE ENGINE AS PER INSTALLATION ENGINE AS PER INSTALLATION INSTRUCTIONS.INSTRUCTIONS.MOUNT CARBURETOR TO ENGINE, MOUNT CARBURETOR TO ENGINE, SECURED AND SAFETIED, THEN FUEL LINES SECURED AND SAFETIED, THEN FUEL LINES AND CONTROLS ARE RECONNECTED.AND CONTROLS ARE RECONNECTED.TIGHTEN FITTING TO THE TORQUE AS TIGHTEN FITTING TO THE TORQUE AS RECOMMENDED.RECOMMENDED.CHECK CONTROLS FOR FREE MOVEMENT CHECK CONTROLS FOR FREE MOVEMENT AND FULL RANGE OF TRAVEL.AND FULL RANGE OF TRAVEL.‘‘STOP’ AT CARBURETOR MUST REACHED STOP’ AT CARBURETOR MUST REACHED BEFORE COCKPIT STOP.BEFORE COCKPIT STOP.


CHECK FOR CHECK FOR SPRINGBACK SPRINGBACK ON THE ON THE CONTROL.CONTROL.MUST BE EQUAL AMOUNT FOR FULL OPEN MUST BE EQUAL AMOUNT FOR FULL OPEN AND FULL CLOSE POSITIONS.AND FULL CLOSE POSITIONS.ONCE INSTALLATION AND RIGGING ONCE INSTALLATION AND RIGGING COMPLETED, ENGINE RUN TO VERIFY COMPLETED, ENGINE RUN TO VERIFY PROPER PERFORMANCE.PROPER PERFORMANCE.CHECKED INCLUDE IDLE MIXTURE AND IDLE CHECKED INCLUDE IDLE MIXTURE AND IDLE RPM (ADJUSTED AS REQUIRED).RPM (ADJUSTED AS REQUIRED).ONCE COMPLETED, CONTROL TO IDLE-CUT ONCE COMPLETED, CONTROL TO IDLE-CUT OFF AND PROMPT ENGINE SHUTDOWN. OFF AND PROMPT ENGINE SHUTDOWN.


PRESSURE INJECTION

CARBURETORS

PRESSURE INJECTION CARBURETORSPRESSURE INJECTION CARBURETORS NOT USED ON MODERN A/C.NOT USED ON MODERN A/C. HAVE SOME BASIC UNDERSTANDING IN HAVE SOME BASIC UNDERSTANDING IN

CASE COME ACROSS ONE OF IT.CASE COME ACROSS ONE OF IT. CARBURETOR DIFFERENT FROM FLOAT-CARBURETOR DIFFERENT FROM FLOAT-

TYPE.TYPE. FUEL DELIVER UNDER PRESSURE BY FUEL FUEL DELIVER UNDER PRESSURE BY FUEL

PUMP THROUGH CARBURETOR AND OUT PUMP THROUGH CARBURETOR AND OUT TO DISCHARGE NOZZLE.TO DISCHARGE NOZZLE.

NO FLOAT CHAMBER NECESSARY TO NO FLOAT CHAMBER NECESSARY TO STORE FUEL.STORE FUEL.

NO NEED TO PLACE DISCHARGE NOZZLE IN NO NEED TO PLACE DISCHARGE NOZZLE IN THE VENTURI, REDUCE CARBURETOR THE VENTURI, REDUCE CARBURETOR ICING AND AIDS IN FUEL VAPORIZATIONICING AND AIDS IN FUEL VAPORIZATION

THE BENDIX PS78D THE BENDIX PS78D PRESSURE CARBURETORPRESSURE CARBURETOR

MAIN METERING.MAIN METERING.

PURPOSE IS TO SUPPLY THE CORRECT PURPOSE IS TO SUPPLY THE CORRECT AMOUNT OF FUEL TO THE ENGINE.AMOUNT OF FUEL TO THE ENGINE.

COMPRISED OF:COMPRISED OF:

– A FUEL REGULATOR OR FUEL CONTROL A FUEL REGULATOR OR FUEL CONTROL UNIT,UNIT,

– A MAIN METERING JET, ANDA MAIN METERING JET, AND– A THROTTLE VALVE.A THROTTLE VALVE.

FUEL REGULATOR OR FUEL CONTROL UNIT FUEL REGULATOR OR FUEL CONTROL UNIT (FCU) (FCU) METERED FUEL FOR ENGINE METERED FUEL FOR ENGINE OPERATION.OPERATION.

CONSIST OF FIVE CHAMBERS, AN INNER CONSIST OF FIVE CHAMBERS, AN INNER AND OUTER DIAPHRAGM, POPPET VALVE AND OUTER DIAPHRAGM, POPPET VALVE ASSEMBLY AND MAIN METERING JET.ASSEMBLY AND MAIN METERING JET.

FILTERED AIR ENTER THE CARBURETOR.FILTERED AIR ENTER THE CARBURETOR. PORTION OF THE AIR FLOWS INTO IMPACT PORTION OF THE AIR FLOWS INTO IMPACT

ANNULUS AROUND THE VENTURI, ITS ANNULUS AROUND THE VENTURI, ITS VELOCITY DECREASE AND PRESSURE VELOCITY DECREASE AND PRESSURE INCREASE.INCREASE.

IMPACT AIR THEN DIRECTED INTO IMPACT AIR THEN DIRECTED INTO CHAMBER ‘A’ OF THE REGULATOR UNIT, CHAMBER ‘A’ OF THE REGULATOR UNIT, PRESSES AGAINST ONE SIDE OF THE PRESSES AGAINST ONE SIDE OF THE INNER DIAPHRAGM.INNER DIAPHRAGM.

FUEL CONTROL UNITFUEL CONTROL UNIT

LOW PRESSURE WITHIN THE VENTURI IS LOW PRESSURE WITHIN THE VENTURI IS VENTED TO CHAMBER ‘B’, ACT ON THE VENTED TO CHAMBER ‘B’, ACT ON THE OPPOSITE SIDE OF THE INNER OPPOSITE SIDE OF THE INNER DIAPHRAGM.DIAPHRAGM.

THE DIFFERENCE PRESSURE BETWEEN THE DIFFERENCE PRESSURE BETWEEN CHAMBER ‘A’ AND ‘B’ CAUSES THE INNER CHAMBER ‘A’ AND ‘B’ CAUSES THE INNER DIAPHRAGM TO MOVE TO THE RIGHT.DIAPHRAGM TO MOVE TO THE RIGHT.

THIS PRESSURE DIFFERENTIAL BETWEEN THIS PRESSURE DIFFERENTIAL BETWEEN CHAMBER ‘A’ AND ‘B’ IS KNOWN AS CHAMBER ‘A’ AND ‘B’ IS KNOWN AS AIR AIR METERING FORCE METERING FORCE AND IS PROPORTIONAL AND IS PROPORTIONAL TO AMOUNT OF AIR FLOWS THROUGH TO AMOUNT OF AIR FLOWS THROUGH VENTURI.VENTURI.

FUEL CONTROL UNIT FUEL CONTROL UNIT CONT.CONT.

FUEL CONTROL UNITFUEL CONTROL UNIT

AS AIR METERING FORCE INCREASES, IT AS AIR METERING FORCE INCREASES, IT OVERCOMES SPRING TENSION AND OPENS A OVERCOMES SPRING TENSION AND OPENS A POPPET VALVE.POPPET VALVE.

A REGULATED AMOUNT OF PRESSURIZED FUEL A REGULATED AMOUNT OF PRESSURIZED FUEL FLOWS INTO CHAMBER ‘D’ AND PUSHES AGAINST FLOWS INTO CHAMBER ‘D’ AND PUSHES AGAINST THE OUTER REGULATOR DIAPHRAGM IN AN THE OUTER REGULATOR DIAPHRAGM IN AN ATTEMPT TO CLOSE THE POPPET VALVE.ATTEMPT TO CLOSE THE POPPET VALVE.

THE FUEL METERING FORCE BALANCES THE AIR THE FUEL METERING FORCE BALANCES THE AIR METERING FORCE TO HOLD THE POPPET VALVE METERING FORCE TO HOLD THE POPPET VALVE OFF IT SEAT AN AMOUNT PROPORTIONAL TO THE OFF IT SEAT AN AMOUNT PROPORTIONAL TO THE VOLUME OF AIR ENTERING THE ENGINE.VOLUME OF AIR ENTERING THE ENGINE.

WHEN ENGINE IS IDLING, INSUFFICIENT AMOUNT OF WHEN ENGINE IS IDLING, INSUFFICIENT AMOUNT OF AIRFLOW EXIST TO PRODUCE A STEADY AIR AIRFLOW EXIST TO PRODUCE A STEADY AIR METERING FORCE TO OPEN THE POPPET VALVE.METERING FORCE TO OPEN THE POPPET VALVE.

AT IDLE SPEEDAT IDLE SPEED, A COIL SPRING TENSION FORCES , A COIL SPRING TENSION FORCES SUPPLEMENT AIR METERING FORCE, FORCES THE SUPPLEMENT AIR METERING FORCE, FORCES THE DIAPHRAGM OVER AND OPENS THE POPPET VALVE DIAPHRAGM OVER AND OPENS THE POPPET VALVE TO PROVIDE FUEL PRESSURE FOR ENGINE TO IDLE.TO PROVIDE FUEL PRESSURE FOR ENGINE TO IDLE.

FUEL CONTROL UNIT FUEL CONTROL UNIT cont.cont.

THE REGULATED FUEL FILLS CHAMBER ‘D’, THE REGULATED FUEL FILLS CHAMBER ‘D’, PASSES THROUGH METERING JET INTO PASSES THROUGH METERING JET INTO CHAMBER ‘C’.CHAMBER ‘C’.

CONSIDERED TO BE METERED FUEL AND ITS CONSIDERED TO BE METERED FUEL AND ITS PRESSURE REMAINS CONSTANT DURING ALL PRESSURE REMAINS CONSTANT DURING ALL ENGINE OPERATIONS.ENGINE OPERATIONS.

METERED FUEL FROM CHAMBER ‘C’ IS ROUTED METERED FUEL FROM CHAMBER ‘C’ IS ROUTED THROUGH IDLE NEEDLE VALVE AND DISCHARGE THROUGH IDLE NEEDLE VALVE AND DISCHARGE VALVE BEFORE DISCHARGED OUT OF THE VALVE BEFORE DISCHARGED OUT OF THE DISCHARGE NOZZLE.DISCHARGE NOZZLE.

AT ALL POWER SETTING ABOVE IDLE, A AT ALL POWER SETTING ABOVE IDLE, A COMBINATION OF SPRING PRESSURE AND LOW COMBINATION OF SPRING PRESSURE AND LOW PRESSURE ON THE BACKSIDE OF A DIAPHRAGM PRESSURE ON THE BACKSIDE OF A DIAPHRAGM HOLD THE IDLE VALVE OPEN FAR ENOUGH THAT HOLD THE IDLE VALVE OPEN FAR ENOUGH THAT IT DOES NOT OBSTRUCT FUEL FLOW.IT DOES NOT OBSTRUCT FUEL FLOW.

FUEL CONTROL UNITFUEL CONTROL UNIT cont. cont.

IDLE AND DISCHARGE VALVEIDLE AND DISCHARGE VALVE

ABOVE IDLE SPEED FUEL METERING PROVIDED ABOVE IDLE SPEED FUEL METERING PROVIDED BY MAIN METERING JET ONLY.BY MAIN METERING JET ONLY.

AFTER PASSES THROUGH THE IDLE NEEDLE AFTER PASSES THROUGH THE IDLE NEEDLE VALVE, FUEL FLOWS UP TO A DIAPHRAGM TYPE VALVE, FUEL FLOWS UP TO A DIAPHRAGM TYPE DISCHARGE NOZZLE VALVE.DISCHARGE NOZZLE VALVE.

DISCHARGE NOZZLE IS SPRING LOADED TO DISCHARGE NOZZLE IS SPRING LOADED TO CLOSE POSITION AND OPEN BY THE CLOSE POSITION AND OPEN BY THE COMBINATION OF FUEL PRESSURE AND LOW COMBINATION OF FUEL PRESSURE AND LOW PRESSURE ON THE BACK SIDE OF A DIAPHRAGM.PRESSURE ON THE BACK SIDE OF A DIAPHRAGM.

PRIMARY PURPOSE OF THE DISCHARGE VALVE IS PRIMARY PURPOSE OF THE DISCHARGE VALVE IS TO MAINTAIN CONSTANT FUEL PRESSURE AFTER TO MAINTAIN CONSTANT FUEL PRESSURE AFTER THE MAIN METERING JET.THE MAIN METERING JET.

DISCHARGE VALVE PROVIDE POSITIVE FUEL CUT-DISCHARGE VALVE PROVIDE POSITIVE FUEL CUT-OFF WHEN MIXTURE CONTROL IS PLACED IN IDLE OFF WHEN MIXTURE CONTROL IS PLACED IN IDLE CUT-OFF POSITION.CUT-OFF POSITION.


DISCHARGE NOZZLE PLACED AFTER THE VENTURI DISCHARGE NOZZLE PLACED AFTER THE VENTURI AND THROTTLE VALVE, NO ICING PROBLEM. FUEL AND THROTTLE VALVE, NO ICING PROBLEM. FUEL PRESSURE FORCES FUEL OUT OF THE DISCHARGE PRESSURE FORCES FUEL OUT OF THE DISCHARGE NOZZLE.NOZZLE.

ONCE FUEL REACH DISCHARGE NOZZLE, AIR FROM ONCE FUEL REACH DISCHARGE NOZZLE, AIR FROM IMPACT ANNULUS MIXED WITH FUEL IN THE IMPACT ANNULUS MIXED WITH FUEL IN THE DISCHARGE NOZZLE ACT AS AIR BLEED TO DISCHARGE NOZZLE ACT AS AIR BLEED TO DESTROY FUEL SURFACE TENSION TO AID IN DESTROY FUEL SURFACE TENSION TO AID IN VAPORIZATION.VAPORIZATION.

COIL SPRING HOLD THE POPPET VALVE OPEN TO COIL SPRING HOLD THE POPPET VALVE OPEN TO LET IDLING FUEL IN, BUT ITS CANNOT PRECISELY LET IDLING FUEL IN, BUT ITS CANNOT PRECISELY METER THE FUEL TO THE DISCHARGE NOZZLE SO METER THE FUEL TO THE DISCHARGE NOZZLE SO IDLE NEEDLE VALVE IS USED TO CONTROL THE IDLE NEEDLE VALVE IS USED TO CONTROL THE AMOUNT OF FUEL ACTUALLY FLOWS TO THE AMOUNT OF FUEL ACTUALLY FLOWS TO THE DISCHARGE NOZZLE.DISCHARGE NOZZLE.

THE EXACT AMOUNT THE IDLE NEEDLE VALVE THE EXACT AMOUNT THE IDLE NEEDLE VALVE OPEN DETERMINE BY THE NEEDLE SPEED OPEN DETERMINE BY THE NEEDLE SPEED ADJUSTMENT ATTACHED TO THE THROTTLE SHAFT. ADJUSTMENT ATTACHED TO THE THROTTLE SHAFT.


MIXTURE CONTROLMIXTURE CONTROL AMOUNT OF FUEL FLOWS TO THE AMOUNT OF FUEL FLOWS TO THE

DISCHARGE NOZZLE DETERMINE BY THE DISCHARGE NOZZLE DETERMINE BY THE PRESS. DIFFERENTIAL BETWEEN CHAMBER PRESS. DIFFERENTIAL BETWEEN CHAMBER ‘A’ AND CHAMBER ‘B’.‘A’ AND CHAMBER ‘B’.

CONTROLLING THE PRESSURE CONTROLLING THE PRESSURE DIFFERENTIAL BETWEEN THIS TWO DIFFERENTIAL BETWEEN THIS TWO CHAMBERS EITHER MANUALLY OR CHAMBERS EITHER MANUALLY OR AUTOMATICALLY.AUTOMATICALLY.

REGULATE THE RATIO OF FUEL AND AIR REGULATE THE RATIO OF FUEL AND AIR SUPPLIED TO THE ENGINE.SUPPLIED TO THE ENGINE.

ALLOW OPERATOR TO CONTROL THE ALLOW OPERATOR TO CONTROL THE FUEL/AIR MIXTURE FOR ENGINE TO FUEL/AIR MIXTURE FOR ENGINE TO OPERATE EFFICIENCY AT VARIOUS OPERATE EFFICIENCY AT VARIOUS ALTITUDES.ALTITUDES.

MANUAL CONTROLMANUAL CONTROL..SIZE OF AIR BLEED DETERMINE BY THE SIZE OF AIR BLEED DETERMINE BY THE POSITION OF NEEDLE VALVE THAT IS POSITION OF NEEDLE VALVE THAT IS CONTROLLED FROM COCKPIT.CONTROLLED FROM COCKPIT.FULL RICH -- VALVE CLOSE, MAXIMUN FULL RICH -- VALVE CLOSE, MAXIMUN PRESSURE DIFFERENTIAL EXIST BETWEEN PRESSURE DIFFERENTIAL EXIST BETWEEN CHAMBER ‘A’ & ‘B’.CHAMBER ‘A’ & ‘B’.IF MIXTURE CONTROL PULL OUT, VALVE OFF IF MIXTURE CONTROL PULL OUT, VALVE OFF SEAT AND PRESSURE DIFFERENTIAL SEAT AND PRESSURE DIFFERENTIAL DECREASED.DECREASED.IN ADDITION, AN IDLE-CUT OFF IS PROVIDED SO IN ADDITION, AN IDLE-CUT OFF IS PROVIDED SO FUEL FLOW CAN BE COMPLETELY STOP.FUEL FLOW CAN BE COMPLETELY STOP.SPRING IN CHAMBER ‘A’ USED TO HOLD SPRING IN CHAMBER ‘A’ USED TO HOLD POPPET VALVE OPEN OFF SEAT WHEN POPPET VALVE OPEN OFF SEAT WHEN INSUFFICIENT PRESSURE DIFFERENTIAL EXIST.INSUFFICIENT PRESSURE DIFFERENTIAL EXIST.

MIXTURE CONTROLMIXTURE CONTROL cont cont

TO CLOSE THE POPPET VALVE TO CLOSE THE POPPET VALVE COMPLETELY IS BY REMOVING SPRING COMPLETELY IS BY REMOVING SPRING PRESSURE FROM THE INNER DIAPHRAGM.PRESSURE FROM THE INNER DIAPHRAGM.RELEASE CONTACT LEVER EXTEND FROM RELEASE CONTACT LEVER EXTEND FROM CHAMBER ‘A’ OUT TO THE MIXTURE CHAMBER ‘A’ OUT TO THE MIXTURE CONTROL.CONTROL.MIXTURE CONTROL IN IDLE-CUTOFF, THE MIXTURE CONTROL IN IDLE-CUTOFF, THE RELEASE CONTACT LEVER COMPRESSES RELEASE CONTACT LEVER COMPRESSES THE IDLE SPRING AND REMOVE ALL THE IDLE SPRING AND REMOVE ALL PRESSURE FROM THE DIAPHRAGM.PRESSURE FROM THE DIAPHRAGM.NO PRESSURE ON THE DIAPHRAGM, NO PRESSURE ON THE DIAPHRAGM, POPPET VALVE CLOSES AND CUT-OFF POPPET VALVE CLOSES AND CUT-OFF FUEL FLOW TO CARBURETOR.FUEL FLOW TO CARBURETOR.

MIXTURE CONTROLMIXTURE CONTROL cont cont

CONTROL OFCONTROL OFFUEL AIR MIXTUREFUEL AIR MIXTURE

AUTOMATIC MIXTURE CONTROL (AMC)AUTOMATIC MIXTURE CONTROL (AMC)A BRASS BELLOW FILLED WITH HELIUM ATTACHED A BRASS BELLOW FILLED WITH HELIUM ATTACHED TO A REVERSE TAPERED NEEDLE.TO A REVERSE TAPERED NEEDLE.AMC MAINTAINS THE PRESSURE DIFFERENTIAL AMC MAINTAINS THE PRESSURE DIFFERENTIAL ACROSS THE INNER REGULATOR DIAPHRAGM BY ACROSS THE INNER REGULATOR DIAPHRAGM BY VARYING THE SIZE OF THE AIR BLEED BETWEEN VARYING THE SIZE OF THE AIR BLEED BETWEEN CHAMBER ‘A’ AND ‘B’.CHAMBER ‘A’ AND ‘B’.WHEN PRESS. IS HIGH, BELLOW CONTRACTS AND WHEN PRESS. IS HIGH, BELLOW CONTRACTS AND SEAT ON THE THICK PART OF THE NEEDLE VALVE, SEAT ON THE THICK PART OF THE NEEDLE VALVE, DECREASE THE SIZE OF THE AIR BLEED OPENING, DECREASE THE SIZE OF THE AIR BLEED OPENING, ALLOWS MAX. PRESSURE DIFFERENTIAL BETWEEN ALLOWS MAX. PRESSURE DIFFERENTIAL BETWEEN CHAMBER ‘A’ AND ‘B’.CHAMBER ‘A’ AND ‘B’.AS A/C CLIMBS, AIR DENSITY DECREASES, BELLOW AS A/C CLIMBS, AIR DENSITY DECREASES, BELLOW EXPANDS AND ALLOW MORE AIR TO BLEED EXPANDS AND ALLOW MORE AIR TO BLEED BETWEEN THE TWO CHAMBERS, REDUCE PRESS. BETWEEN THE TWO CHAMBERS, REDUCE PRESS. DIFFERENTIAL ACROSS THE INNER REGULATOR DIFFERENTIAL ACROSS THE INNER REGULATOR DIAPHRAGM, WHICH CLOSES THE POPPET VALVE DIAPHRAGM, WHICH CLOSES THE POPPET VALVE SLIGHTLY AND REDUCE FUEL FLOW TO THE SLIGHTLY AND REDUCE FUEL FLOW TO THE DISCHARGE NOZZLE.DISCHARGE NOZZLE.


ACCELERATION SYSTEMACCELERATION SYSTEMTO PROVIDE AN IMMEDIATE BUT BRIEF INCREASE TO PROVIDE AN IMMEDIATE BUT BRIEF INCREASE IN FUEL FLOW TO THE CARBURETOR BY A SINGLE IN FUEL FLOW TO THE CARBURETOR BY A SINGLE DIAPHRAGM PUMP.DIAPHRAGM PUMP.CONSISTS OF THREE CHAMBERS;CONSISTS OF THREE CHAMBERS;

1. AIR CHAMBER.1. AIR CHAMBER. 2. PRIMARY FUEL CHAMBER.2. PRIMARY FUEL CHAMBER. 3. SECONDARY FUEL CHAMBER.3. SECONDARY FUEL CHAMBER.

AIR CHAMBER AND PRIMARY FUEL CHAMBER IS AIR CHAMBER AND PRIMARY FUEL CHAMBER IS SEPARATED BY A DIAPHRAGM.SEPARATED BY A DIAPHRAGM.PRIMARY AND SECONDARY FUEL CHAMBER PRIMARY AND SECONDARY FUEL CHAMBER SEPARATED BY A RIGID DIVIDER, COMBINATION SEPARATED BY A RIGID DIVIDER, COMBINATION CHECK/RELIEF VALVE AND A SINGLE FUEL BLEED.CHECK/RELIEF VALVE AND A SINGLE FUEL BLEED.WHEN ENGINE IS STARTED THE MANIFOLD WHEN ENGINE IS STARTED THE MANIFOLD PRESSURE DECREASES AND PARTLY PRESSURE DECREASES AND PARTLY COMPRESSES THE SPRING IN THE ACCELERATOR COMPRESSES THE SPRING IN THE ACCELERATOR PUMP AIR CHAMBER.PUMP AIR CHAMBER.FUEL FILLS THE TWO FUEL CHAMBERS.FUEL FILLS THE TWO FUEL CHAMBERS.

WHEN THROTTLE OPENED RAPIDLY, MANIFOLD WHEN THROTTLE OPENED RAPIDLY, MANIFOLD PRESSURE INCREASES AND FORCE THE DIAPHRAGM PRESSURE INCREASES AND FORCE THE DIAPHRAGM OVER.OVER.THIS FORCES FUEL FROM PRIMARY CHAMBER INTO THIS FORCES FUEL FROM PRIMARY CHAMBER INTO SECONDARY CHAMBER AND ONTO DISCHARGE SECONDARY CHAMBER AND ONTO DISCHARGE NOZZLE.NOZZLE.THE VALVE SOON SEATS AFTER THE INITIAL SURGE.THE VALVE SOON SEATS AFTER THE INITIAL SURGE.THE REMAINING FUEL DISCHARGE THROUGH THE FUEL THE REMAINING FUEL DISCHARGE THROUGH THE FUEL BLEED TO PROVIDE SUSTAINED STREAM OF FUEL TO BLEED TO PROVIDE SUSTAINED STREAM OF FUEL TO THE DISCHARGE NOZZLE.THE DISCHARGE NOZZLE.THROTTLE BACKUP RAPIDLY – MANIFOLD PRESSURE THROTTLE BACKUP RAPIDLY – MANIFOLD PRESSURE DECREASES CAUSE THE PUMP SPRING TO COLLAPSE DECREASES CAUSE THE PUMP SPRING TO COLLAPSE RAPIDLY AND DRAW FUEL INTO THE PRIMARY FUEL RAPIDLY AND DRAW FUEL INTO THE PRIMARY FUEL CHAMBER.CHAMBER.TO PREVENT RAPID DIAPHRAGM MOVEMENT FROM TO PREVENT RAPID DIAPHRAGM MOVEMENT FROM STARVING THE DISCHARGE NOZZLE OF FUEL AS THE STARVING THE DISCHARGE NOZZLE OF FUEL AS THE PUMP FILLS, CHECK/RELIEF VALVE REMAINS SEATED PUMP FILLS, CHECK/RELIEF VALVE REMAINS SEATED AND PERMIT FUEL TO FILL PRIMARY FUEL CHAMBER AND PERMIT FUEL TO FILL PRIMARY FUEL CHAMBER THROUGH THE FUEL BLEED ONLY.THROUGH THE FUEL BLEED ONLY.

ACCELERATION SYSTEM ACCELERATION SYSTEM cont.cont.

TYPICAL ACCELERATOR TYPICAL ACCELERATOR PUMPPUMP

POWER ENRICHMENT SYSTEMPOWER ENRICHMENT SYSTEMPROVIDE EXTRA FUEL FOR OPERATION ABOVE CRUISE PROVIDE EXTRA FUEL FOR OPERATION ABOVE CRUISE SETTING, FOR COOLING AND PREVENT DETONATION.SETTING, FOR COOLING AND PREVENT DETONATION.SYSTEM EITHER USE A DOUBLE STEP IDLE VALVE OR SYSTEM EITHER USE A DOUBLE STEP IDLE VALVE OR AIRFLOW POWER ENRICHMENT VALVE.AIRFLOW POWER ENRICHMENT VALVE.THE THE DOUBLE STEP IDLE VALVE DOUBLE STEP IDLE VALVE IS STEPPED TO VARY IS STEPPED TO VARY THE AMOUNT OF FUEL FLOWS TO THE DISCHARGE THE AMOUNT OF FUEL FLOWS TO THE DISCHARGE NOZZLE.NOZZLE.AT LOW POWER SETTING THE FIRST IDLE STEP OF AT LOW POWER SETTING THE FIRST IDLE STEP OF NEEDLE VALVE OFF SEATS ALLOW ONLY IDLE FUEL TO NEEDLE VALVE OFF SEATS ALLOW ONLY IDLE FUEL TO DISCHARGE NOZZLE.DISCHARGE NOZZLE.AS ENGINE ACCELERATED ABOVE IDLE TO CRUISE AS ENGINE ACCELERATED ABOVE IDLE TO CRUISE POWER, VENTURI SUCTION INCREASES AND NEEDLE POWER, VENTURI SUCTION INCREASES AND NEEDLE VALVE OFF SEAT FURTHER TO THE SECOND CRUISE VALVE OFF SEAT FURTHER TO THE SECOND CRUISE STEP OF THE NEEDLE VALVE TO REGULATE FUEL FLOW.STEP OF THE NEEDLE VALVE TO REGULATE FUEL FLOW.ABOVE CRUISE POWER, VENTURI SUCTION INCREASES ABOVE CRUISE POWER, VENTURI SUCTION INCREASES ENOUGH TO COMPLETELY OFF SEAT (OPEN) THE ENOUGH TO COMPLETELY OFF SEAT (OPEN) THE NEEDLE VALVE, SO ADDITIONAL FUEL CAN FLOW TO THE NEEDLE VALVE, SO ADDITIONAL FUEL CAN FLOW TO THE DISCHARGE NOZZLE TO ENRICHEN THE MIXTURE.DISCHARGE NOZZLE TO ENRICHEN THE MIXTURE.HIGH POWER SETTING, MAIN METERING JET LIMIT THE HIGH POWER SETTING, MAIN METERING JET LIMIT THE FUEL FLOW.FUEL FLOW.

A DOUBLE STEPPED A DOUBLE STEPPED IDLE VALVEIDLE VALVE

AIRFLOW ENRICHMENT VALVE AIRFLOW ENRICHMENT VALVE LOCATED IN THE FUEL LOCATED IN THE FUEL PASSAGE PARALLEL WITH MAIN METERING JET.PASSAGE PARALLEL WITH MAIN METERING JET.CONSIST OF A NEEDLE VALVE ASSEMBLY THAT SENSES CONSIST OF A NEEDLE VALVE ASSEMBLY THAT SENSES THE PRESSURE DROP IN THE VENTURI TO DETERMINE THE PRESSURE DROP IN THE VENTURI TO DETERMINE WHEN THE ENGINE IS OPERATING AT HIGH POWER WHEN THE ENGINE IS OPERATING AT HIGH POWER LEVELS.LEVELS.CRUISE POWER SETTING SPRING PRESSURE HOLD THE CRUISE POWER SETTING SPRING PRESSURE HOLD THE ENRICHMENT VALVE CLOSED, MAIN METERING JET ENRICHMENT VALVE CLOSED, MAIN METERING JET LIMITS FUEL FLOW TO THE DISCHARGE NOZZLE.LIMITS FUEL FLOW TO THE DISCHARGE NOZZLE.POWER INCREASES ABOVE CRUISE THE AMOUNT OF AIR POWER INCREASES ABOVE CRUISE THE AMOUNT OF AIR FLOWING THROUGH THE VENTURI INCREASES.FLOWING THROUGH THE VENTURI INCREASES.INCREASES IN AIRFLOW CAUSE AIR PRESSURE WITHIN INCREASES IN AIRFLOW CAUSE AIR PRESSURE WITHIN ENRICHMENT VALVE HOUSING DECREASES ENOUGH TO ENRICHMENT VALVE HOUSING DECREASES ENOUGH TO OFF SEAT THE ENRICHMENT NEEDLE VALVE.OFF SEAT THE ENRICHMENT NEEDLE VALVE.AS THE ENRICHMENT VALVE OPENS, FUEL BYPASS AS THE ENRICHMENT VALVE OPENS, FUEL BYPASS METERING JET, INCREASES AMOUNT OF FUEL FLOW TO METERING JET, INCREASES AMOUNT OF FUEL FLOW TO THE DISCHARGE NOZZLE AND ENRICHES THE FUEL THE DISCHARGE NOZZLE AND ENRICHES THE FUEL MIXTURE.MIXTURE.

POWER ENRICHMENT SYSTEM POWER ENRICHMENT SYSTEM cont.cont.

TYPICAL AIRFLOW TYPICAL AIRFLOW ENRICHMENT VALVEENRICHMENT VALVE

WATER INJECTION WATER INJECTION USED ON LARGE ENGINE TO USED ON LARGE ENGINE TO ALLOW ENGINE TO PRODUCE MAXIMUN POWER ALLOW ENGINE TO PRODUCE MAXIMUN POWER WITHOUT DETONATION AND PREIGNITION.WITHOUT DETONATION AND PREIGNITION.WATER INJECTION SYSTEM (ANTI-DETONATION WATER INJECTION SYSTEM (ANTI-DETONATION INJECTION OR ADI SYSTEM) USE A MIXTURE OF INJECTION OR ADI SYSTEM) USE A MIXTURE OF WATER AND ALCOHOL INJECTED INTO THE WATER AND ALCOHOL INJECTED INTO THE CARBURETOR TO CREATE FUEL/AIR MIXTURE THAT CARBURETOR TO CREATE FUEL/AIR MIXTURE THAT HELPS PREVENT DETONATION.HELPS PREVENT DETONATION.NORMALLY CARBURETOR PROVIDE RICH MIXTURE NORMALLY CARBURETOR PROVIDE RICH MIXTURE DURING HIGH POWER OPERATION.DURING HIGH POWER OPERATION.EXTRA FUEL HELPS TO COOL THE ENGINE AND EXTRA FUEL HELPS TO COOL THE ENGINE AND REDUCE THE CHANCE OF DETONATION.REDUCE THE CHANCE OF DETONATION.DISADVANTAGE OF RICH MIXTURE DOES NOT DISADVANTAGE OF RICH MIXTURE DOES NOT ALLOW THE ENGINE TO PRODUCE MAXIMUN ALLOW THE ENGINE TO PRODUCE MAXIMUN POWER OUTPUT.POWER OUTPUT.IF THE SYSTEM USED ANTI-DETONATION SYSTEM IF THE SYSTEM USED ANTI-DETONATION SYSTEM THE FUEL/AIR MIXTURE CAN BE LEANED TO ALLOW THE FUEL/AIR MIXTURE CAN BE LEANED TO ALLOW ENGINE TO PRODUCE ITS MAXIMUM POWER.ENGINE TO PRODUCE ITS MAXIMUM POWER.

POWER ENRICHMENT SYSTEM POWER ENRICHMENT SYSTEM contcont

PRESSURE CARBURETOR MAINTENANCEPRESSURE CARBURETOR MAINTENANCE

INTERNAL MAINTENANCE ENTAILS USE OF FLOW INTERNAL MAINTENANCE ENTAILS USE OF FLOW BENCH AND SPECIALIZED TOOLS.BENCH AND SPECIALIZED TOOLS.MAINTENANCE GENERALLY LIMITED TO INSPECTION, MAINTENANCE GENERALLY LIMITED TO INSPECTION, INSTALLATION, REMOVAL AND FIELD ADJUSTMENT.INSTALLATION, REMOVAL AND FIELD ADJUSTMENT.CHECK FOR SECURITY, DAMAGE AND POSSIBLE CHECK FOR SECURITY, DAMAGE AND POSSIBLE LEAK AT MATING SURFACE.LEAK AT MATING SURFACE.IF LEAK, WILL CAUSE LEANER MIXTURE AND COULD IF LEAK, WILL CAUSE LEANER MIXTURE AND COULD LEAD TO DETONATION AND ENGINE DAMAGE.LEAD TO DETONATION AND ENGINE DAMAGE.INSPECTION INCLUDED SECURITY OF ALL THE INSPECTION INCLUDED SECURITY OF ALL THE CONTROL LINKAGES.CONTROL LINKAGES.IDLE MIXTURE AND IDLE SPEED ADJUSTMENT TO BE IDLE MIXTURE AND IDLE SPEED ADJUSTMENT TO BE CARRIED OUT AFTER CARBURETOR MAINTENANCE CARRIED OUT AFTER CARBURETOR MAINTENANCE AS PER MAINTENANCE MANUAL / CARBURETOR AS PER MAINTENANCE MANUAL / CARBURETOR MAINTENANCE MANUAL.MAINTENANCE MANUAL.TYPICAL SAME PROCEDURE USE ON FLOAT-TYPE TYPICAL SAME PROCEDURE USE ON FLOAT-TYPE CARBURETOR IS APPLICABLE.CARBURETOR IS APPLICABLE.

IDLE MIXTURE AND SPEED IDLE MIXTURE AND SPEED ADJUSTMENT SCREWSADJUSTMENT SCREWS

CARBURETOR OVERHAULCARBURETOR OVERHAULOVERHAUL OF A PRESSURE CARBURETOR OVERHAUL OF A PRESSURE CARBURETOR CONDUCTED BY THE MANUFACTURER OR A CONDUCTED BY THE MANUFACTURER OR A CERTIFICATED REPAIR FACILITY.CERTIFICATED REPAIR FACILITY.

ALL FRESHLY OVERHAULED CARBURETOR ALL FRESHLY OVERHAULED CARBURETOR FILLED WITH PRESERVATIVE OIL SHALL BE FILLED WITH PRESERVATIVE OIL SHALL BE REMOVED BEFORE USE.REMOVED BEFORE USE.

MAY REQUIRED THAT CARBURETOR MAY REQUIRED THAT CARBURETOR SUBMERGE OR FILLED WITH FUEL TO SUBMERGE OR FILLED WITH FUEL TO SPECIFIED TIME TO LIMBER UP ALL SPECIFIED TIME TO LIMBER UP ALL DIAPHRAGMS.DIAPHRAGMS.

INSTALLATION VARY FROM ENGINE TO INSTALLATION VARY FROM ENGINE TO ENGINE, REFER TO THE APPROPRIATED ENGINE, REFER TO THE APPROPRIATED INSTALLATION INSTRUCTIONS. INSTALLATION INSTRUCTIONS.

FUEL FUEL

INJECTIONINJECTION

SYSTEMSYSTEM

FUEL INJECTION SYSTEMFUEL INJECTION SYSTEM ALTHOUGH CARBURETOR PROVIDE RELIABLE ALTHOUGH CARBURETOR PROVIDE RELIABLE

MEANS OF METERING THE AMOUNT OF FUEL MEANS OF METERING THE AMOUNT OF FUEL INTO AN ENGINE, THEY DO HAVE TWO MAJOR INTO AN ENGINE, THEY DO HAVE TWO MAJOR LIMITATIONS.LIMITATIONS.

INTAKE MANIFOLD DIFFER IN LENGTH AND INTAKE MANIFOLD DIFFER IN LENGTH AND SHAPE, MIXTURE NOT DISTRIBUTE EVENLY IN SHAPE, MIXTURE NOT DISTRIBUTE EVENLY IN CARBURETED ENGINE.CARBURETED ENGINE.

WITH HIGH COMPRESSION RATIO ENGINE, A WITH HIGH COMPRESSION RATIO ENGINE, A LEAN MIXTURE IN ANY ONE CYLINDER CAN LEAN MIXTURE IN ANY ONE CYLINDER CAN RESULT IN DETONATION AND POSSIBLE RESULT IN DETONATION AND POSSIBLE ENGINE DAMAGE.ENGINE DAMAGE.

DISADVANTAGE IS SUSCEPTIBILITY TO DISADVANTAGE IS SUSCEPTIBILITY TO CARBURETOR ICING.CARBURETOR ICING.

TO OVERCOME THIS LIMITATIONS, FUEL TO OVERCOME THIS LIMITATIONS, FUEL INJECTION SYSTEM HAVE BEEN INJECTION SYSTEM HAVE BEEN INCORPORATED. INCORPORATED.

DIRECT FUEL INJECTION SYSTEMDIRECT FUEL INJECTION SYSTEM

FUEL IS INJECTED DIRECTLY INTO THE FUEL IS INJECTED DIRECTLY INTO THE CYLINDER, OFFER EVEN FUEL DISTRIBUTION CYLINDER, OFFER EVEN FUEL DISTRIBUTION AND REDUCED BACKFIRING.AND REDUCED BACKFIRING.

PUMP FORCED METERED FUEL DIRECTLY PUMP FORCED METERED FUEL DIRECTLY INTO THE INDIVIDUAL CYLINDERS AS TIMED, INTO THE INDIVIDUAL CYLINDERS AS TIMED, WITH HIGH PRESSURE SPURTS.WITH HIGH PRESSURE SPURTS.

USED ON EARLY RADIAL ENGINE.USED ON EARLY RADIAL ENGINE. IMPRACTICAL AND TOO EXPENSIVE DUE TO IMPRACTICAL AND TOO EXPENSIVE DUE TO

CLOSE MANUFACTURING TOLERANCE AND CLOSE MANUFACTURING TOLERANCE AND COMPLEX COMPONENTS REQUIRED.COMPLEX COMPONENTS REQUIRED.

CONTINUOUS-FLOW FUEL INJECTION CONTINUOUS-FLOW FUEL INJECTION SYSTEM.SYSTEM.

FUEL IS INJECTED AND MIXED WITH AIR IN FUEL IS INJECTED AND MIXED WITH AIR IN EACH INTAKE PORT JUST BEHIND THE INTAKE EACH INTAKE PORT JUST BEHIND THE INTAKE VALVE.VALVE.

FUEL IS CONTINUOUSLY INJECTED FUEL IS CONTINUOUSLY INJECTED THROUGHOUT THE ENTIRE COMBUSTION THROUGHOUT THE ENTIRE COMBUSTION CYCLE, INSTEAD OF ONLY DURING THE INTAKE CYCLE, INSTEAD OF ONLY DURING THE INTAKE STROKE.STROKE.

ALLOW PLENTY OF TIME FOR FUEL TO ALLOW PLENTY OF TIME FOR FUEL TO VAPORIZE AND MIX WITH AIR BEFORE DRAWN VAPORIZE AND MIX WITH AIR BEFORE DRAWN INTO CYLINDER WHEN INTAKE VALVE OPENS.INTO CYLINDER WHEN INTAKE VALVE OPENS.

TWO TYPES OF CONTINUOUS-FLOW FUEL TWO TYPES OF CONTINUOUS-FLOW FUEL SYSTEMS:SYSTEMS:PRECISION AIRMOTIVE RSA SYSTEM.PRECISION AIRMOTIVE RSA SYSTEM.TELEDYNE CONTINENTAL SYSTEM.TELEDYNE CONTINENTAL SYSTEM.

RSA SYSTEMRSA SYSTEM

PRECISION AIRMOTIVE PRODUCE TWO PRECISION AIRMOTIVE PRODUCE TWO WIDELY USED FUEL METERING SYSTEM WIDELY USED FUEL METERING SYSTEM NAMELY:NAMELY:RS (RECIP. ENGINE-SERVO CONTROL) RS (RECIP. ENGINE-SERVO CONTROL) SYSTEM AND RSA SYSTEM.SYSTEM AND RSA SYSTEM.RSA SYSTEM CONSISTS OF:RSA SYSTEM CONSISTS OF:– VENTURI HOUSING.VENTURI HOUSING.– FUEL METERING UNIT.FUEL METERING UNIT.– FUEL REGULATOR.FUEL REGULATOR.– FLOW DIVIDER.FLOW DIVIDER.– SEVERAL FUEL NOZZLES.SEVERAL FUEL NOZZLES.

11stst step step

Idle level and Idle level and mixture mixture controls controls metered metered amount of amount of fuel to fuel to regulatorregulator

Air and fuel Air and fuel metering metering forces forces regulate fuel regulate fuel to flow divider to flow divider

Flow divider to nozzlesFlow divider to nozzles

Note: Venturi Note: Venturi housing and all housing and all this three units this three units are cast as a are cast as a single unitsingle unit

PRIMARY COMPONENTS OF AN PRIMARY COMPONENTS OF AN RSA FUEL INJECTION SYSTEMRSA FUEL INJECTION SYSTEM

RSA SYSTEMRSA SYSTEM cont. cont.

VENTURI HOUSINGVENTURI HOUSINGCAST OUT OF ALUMINUM AS A SINGLE CAST OUT OF ALUMINUM AS A SINGLE UNIT.UNIT.CONTAIN SINGLE VENTURI CAST ALUMINUM CONTAIN SINGLE VENTURI CAST ALUMINUM PRESSED INTO BOTTOM OF THE HOUSING.PRESSED INTO BOTTOM OF THE HOUSING.THROTTLE VALVE INSTALLED AT TOP OF THROTTLE VALVE INSTALLED AT TOP OF THE VENTURI HOUSING TO CONTROL THE THE VENTURI HOUSING TO CONTROL THE AIRFLOW.AIRFLOW.THREE HOLES DRILLED THROUGH THE THREE HOLES DRILLED THROUGH THE THROTTLE VALVE NEAR ITS EDGES FOR THROTTLE VALVE NEAR ITS EDGES FOR ADEQUATE AIRFLOW FOR ENGINE IDLING.ADEQUATE AIRFLOW FOR ENGINE IDLING.

TYPICAL VENTURI TYPICAL VENTURI HOUSINGHOUSING

THREE HOLES FOR THREE HOLES FOR IDLING AIRFLOWIDLING AIRFLOW

FUEL METERING UNIT FUEL METERING UNIT CONSISTS OF:CONSISTS OF:FUEL STRAINER.FUEL STRAINER.MIXTURE CONTROL AND IDLE VALVE, ANDMIXTURE CONTROL AND IDLE VALVE, ANDA MAIN AND ENRICHMENT METERING JET.A MAIN AND ENRICHMENT METERING JET.MIXTURE AND IDLE VALVES ARE SPRING-MIXTURE AND IDLE VALVES ARE SPRING-LOADED, FLAT PLATE-TYPE VALVES LOADED, FLAT PLATE-TYPE VALVES MECHANICALLY ACTUATED TO CONTROL THE MECHANICALLY ACTUATED TO CONTROL THE AMOUNT OF FUEL FLOW INTO AND OUT OF AMOUNT OF FUEL FLOW INTO AND OUT OF THE METERING JET.THE METERING JET.MIXTURE VALVE IS ACTUATED BY THE MIXTURE VALVE IS ACTUATED BY THE MIXTURE CONTROL IN THE COCKPIT.MIXTURE CONTROL IN THE COCKPIT.IDLE VALVE IS ACTUATED BY THE THROTTLE IDLE VALVE IS ACTUATED BY THE THROTTLE LEVER. LEVER.

RSA SYSTEMRSA SYSTEM cont. cont.

A TYPICAL RSA FUEL A TYPICAL RSA FUEL METERING UNITMETERING UNIT

Fuel metering begin with unmetered Fuel metering begin with unmetered fuel pumped into the fuel metering unit fuel pumped into the fuel metering unit through fuel strainer, passes through a through fuel strainer, passes through a port in the mixture control valveport in the mixture control valve.

FUEL METERING UNITFUEL METERING UNIT MIXTURE CONTROL IS A FLAT MIXTURE CONTROL IS A FLAT

PLATE-TYPE VALVE ROTATED PLATE-TYPE VALVE ROTATED OVER THE PASSAGE WAY OVER THE PASSAGE WAY LEADING TO THE METERING JET.LEADING TO THE METERING JET.

WHEN MIXTURE CONTROL IS WHEN MIXTURE CONTROL IS ADVANCED THE PASSAGE WAY ADVANCED THE PASSAGE WAY LEADING TO THE METERING JET LEADING TO THE METERING JET IS UNCOVERED.IS UNCOVERED.

RICH POSITION, THE OPENING BY RICH POSITION, THE OPENING BY THE MIXTURE CONTROL IS THE MIXTURE CONTROL IS LARGER THAN THE METERING LARGER THAN THE METERING JET.JET.

INTERMEDIATE POSITION, THE INTERMEDIATE POSITION, THE OPENING IS SMALLER THAN THE OPENING IS SMALLER THAN THE MAIN JET AND THE MIXTURE MAIN JET AND THE MIXTURE CONTROL LIMIT THE FLOW.CONTROL LIMIT THE FLOW.

TYPICAL MIXTURE CONTROL VALVETYPICAL MIXTURE CONTROL VALVE

A SECOND PASSAGEWAY IN THE MIXTURE CONTROL A SECOND PASSAGEWAY IN THE MIXTURE CONTROL BASE ALLOW UNMETERED / INLET FUEL PRESSURE TO BASE ALLOW UNMETERED / INLET FUEL PRESSURE TO FLOW TO THE FUEL REGULATOR USED AS REFERENCE FLOW TO THE FUEL REGULATOR USED AS REFERENCE PRESSURE FOR REGULATING THE AMOUNT OF FUEL PRESSURE FOR REGULATING THE AMOUNT OF FUEL FLOWS TO THE ENGINE.FLOWS TO THE ENGINE.

AFTER PASSING THE MIXTURE VALVE, FUEL FLOW AFTER PASSING THE MIXTURE VALVE, FUEL FLOW THROUGH THE METERING JET.THROUGH THE METERING JET.

THE AMOUNT OF FUEL CAN FLOW OUT EITHER MAIN THE AMOUNT OF FUEL CAN FLOW OUT EITHER MAIN OR ENRICHMENT JET IS DETERMINED BY THE OR ENRICHMENT JET IS DETERMINED BY THE POSITION OF THE IDLE VALVE.POSITION OF THE IDLE VALVE.

VALVE PLATE USED WITH IDLE VALVE VALVE PLATE USED WITH IDLE VALVE PROPORTIONATELY UNCOVERS BOTH THE MAIN AND PROPORTIONATELY UNCOVERS BOTH THE MAIN AND ENRICHMENTS WHEN THROTTLE IS ADVANCED.ENRICHMENTS WHEN THROTTLE IS ADVANCED.

LOW POWER SETTING, ONLY SMALL PORTION OF THE LOW POWER SETTING, ONLY SMALL PORTION OF THE MAIN METERING JET IS UNCOVERED.MAIN METERING JET IS UNCOVERED.

THROTTLE FULLY OPENED, BOTH MAIN AND THROTTLE FULLY OPENED, BOTH MAIN AND ENRICHMENT JETS ARE UNCOVERED TO PROVIDE THE ENRICHMENT JETS ARE UNCOVERED TO PROVIDE THE FUEL REQUIRED FOR HIGH POWERFUEL REQUIRED FOR HIGH POWER

FUEL METERING UNITFUEL METERING UNIT

TYPICAL MAIN AND TYPICAL MAIN AND ENRICHMENT JETSENRICHMENT JETS

FUEL REGULATORFUEL REGULATOR

SUPPLY CORRECT AMOUNT OF FUEL TO SUPPLY CORRECT AMOUNT OF FUEL TO THE ENGINE.THE ENGINE.FUEL REGULATOR RECEIVES METERED FUEL REGULATOR RECEIVES METERED FUEL FROM THE FUEL METERING UNIT AND FUEL FROM THE FUEL METERING UNIT AND REGULATE IT TO THE ENGINE, BASE ON REGULATE IT TO THE ENGINE, BASE ON THE AMOUNT OF AIR PASSING THROUGH THE AMOUNT OF AIR PASSING THROUGH THE VENTURI.THE VENTURI.CONSIST OF FOUR CHAMBERS, AIR AND CONSIST OF FOUR CHAMBERS, AIR AND FUEL DIAPHRAGM AND A BALL VALVE.FUEL DIAPHRAGM AND A BALL VALVE.

TYPICAL FUEL REGULATOR OF TYPICAL FUEL REGULATOR OF RSA FUEL INJECTION SYSTEMRSA FUEL INJECTION SYSTEM

FUEL REGULATORFUEL REGULATORAS AIR ENTERS VENTURI HOUSING, SOME AIR FLOWS AS AIR ENTERS VENTURI HOUSING, SOME AIR FLOWS INTO A SERIES OF IMPACT TUBE THAT PROJECT OUT OF INTO A SERIES OF IMPACT TUBE THAT PROJECT OUT OF THE BASE OF THE VENTURI.THE BASE OF THE VENTURI.THE AIR IS DIRECTED INTO A SEAL CHAMBER ACTS ON THE AIR IS DIRECTED INTO A SEAL CHAMBER ACTS ON ONE SIDE OF THE DIAPHRAGM.ONE SIDE OF THE DIAPHRAGM.CHAMBER ON THE OPPOSITE SIDE OF THE AIR CHAMBER ON THE OPPOSITE SIDE OF THE AIR DIAPHRAGM IS VENTED TO THE LOW PRESSURE AIR IN DIAPHRAGM IS VENTED TO THE LOW PRESSURE AIR IN THE VENTURI.THE VENTURI.THE TWO FORCES MOVE THE AIR DIAPHRAGM AN THE TWO FORCES MOVE THE AIR DIAPHRAGM AN AMOUNT PROPORTIONAL TO THE VOLUME OF AIR AMOUNT PROPORTIONAL TO THE VOLUME OF AIR DRAWN THROUGH THE VENTURI.DRAWN THROUGH THE VENTURI.THE FORCE PRODUCE PRESSURE DIFFERENTIAL THE FORCE PRODUCE PRESSURE DIFFERENTIAL ACROSS THE AIR DIAPHRAGM, REFERRED AS AIR ACROSS THE AIR DIAPHRAGM, REFERRED AS AIR METERING FORCE, IS TO OPEN A BALL OR SERVO VALVE METERING FORCE, IS TO OPEN A BALL OR SERVO VALVE ALLOWING FUEL TO FLOW TO THE FLOW DIVIDER.ALLOWING FUEL TO FLOW TO THE FLOW DIVIDER.AT THE SAME TIME THE AIR METERING FORCE OPENS AT THE SAME TIME THE AIR METERING FORCE OPENS THE BALL VALVE, INLET FUEL PRESSURE ACTS ON ONE THE BALL VALVE, INLET FUEL PRESSURE ACTS ON ONE SIDE OF THE FUEL DIAPHRAGM TO MOVE THE BALL SIDE OF THE FUEL DIAPHRAGM TO MOVE THE BALL VALVE TOWARDS CLOSE POSITION.VALVE TOWARDS CLOSE POSITION.

THE METERED FUEL FLOWS INTO THE CHAMBER AND THE METERED FUEL FLOWS INTO THE CHAMBER AND PAST THE BALL VALVE, OPPOSES THE INLET FUEL PAST THE BALL VALVE, OPPOSES THE INLET FUEL PRESSURE TO CREATE A FUEL METERING FORCE THAT PRESSURE TO CREATE A FUEL METERING FORCE THAT BALANCES THE AIR METERING FORCE.BALANCES THE AIR METERING FORCE.WHEN THROTTLE IS ADVANCED, THE IMPACT AIR WHEN THROTTLE IS ADVANCED, THE IMPACT AIR PRESSURE INCREASE, VENTURI PRESSURE DECREASE, PRESSURE INCREASE, VENTURI PRESSURE DECREASE, INCREASING DIFFERENTIAL PRESSURE ACROSS THE AIR INCREASING DIFFERENTIAL PRESSURE ACROSS THE AIR DIAPHRAGM WHICH PULLS THE BALL VALVE FURTHER DIAPHRAGM WHICH PULLS THE BALL VALVE FURTHER OFF ITS SEAT.OFF ITS SEAT.AS THE BALL VALVE OPENS, THE METERED FUEL AS THE BALL VALVE OPENS, THE METERED FUEL PRESSURE DROP, WHILE INLET FUEL PRESSURE REMAIN PRESSURE DROP, WHILE INLET FUEL PRESSURE REMAIN CONSTANT.CONSTANT.THE INCREASED DIFFERENCE BETWEEN THE METERED THE INCREASED DIFFERENCE BETWEEN THE METERED FUEL PRESSURE AND THE INLET FUEL PRESSURE FUEL PRESSURE AND THE INLET FUEL PRESSURE CAUSES MORE FUEL TO FLOW THROUGH THE MAIN CAUSES MORE FUEL TO FLOW THROUGH THE MAIN METERING JET IN THE METERING UNIT AND SEND MORE METERING JET IN THE METERING UNIT AND SEND MORE FUEL PASS THE BALL VALVE ON TO THE ENGINE.FUEL PASS THE BALL VALVE ON TO THE ENGINE.THE FUNCTION OF THE BALL VALVE IS TO CREATE A THE FUNCTION OF THE BALL VALVE IS TO CREATE A PRESSURE DIFFERENTIAL ACROSS THE METERING JET PRESSURE DIFFERENTIAL ACROSS THE METERING JET PROPORTIONAL TO THE AIR FLOW DRAWN TO THE PROPORTIONAL TO THE AIR FLOW DRAWN TO THE ENGINE.ENGINE.

FUEL REGULATORFUEL REGULATOR cont cont

IDLE SYSTEMIDLE SYSTEMAT IDLE, THE AIRFLOW THROUGH THE ENGINE IS LOW AT IDLE, THE AIRFLOW THROUGH THE ENGINE IS LOW AND THE AIR METERING FORCE UNABLE TO OPEN THE AND THE AIR METERING FORCE UNABLE TO OPEN THE BALL VALVE TO MAINTAIN PRESSURE DIFFERENTIAL BALL VALVE TO MAINTAIN PRESSURE DIFFERENTIAL ACROSS THE METERING JET.ACROSS THE METERING JET.TO HOLD THE BALL VALVE OFF ITS SEAT AT IDLE TO HOLD THE BALL VALVE OFF ITS SEAT AT IDLE SPEED, IT IS PROVIDED BY A CONSTANT HEAD IDLE SPEED, IT IS PROVIDED BY A CONSTANT HEAD IDLE SPRING.SPRING.WHEN SMALL AMOUNT OF AIR FLOWING THROUGH THE WHEN SMALL AMOUNT OF AIR FLOWING THROUGH THE VENTURI, THE CONSTANT HEAD SPRING HOLDS THE VENTURI, THE CONSTANT HEAD SPRING HOLDS THE BALL VALVE OFF ITS SEAT.BALL VALVE OFF ITS SEAT.AS INTAKE AIRFLOW INCREASE, THE AIR MOVES AS INTAKE AIRFLOW INCREASE, THE AIR MOVES OUTWARD TO COMPRESS THE CONSTANT HEAD SPRING OUTWARD TO COMPRESS THE CONSTANT HEAD SPRING UNTIL THE DIAPHRAGM BUSHING CONTACTS THE STOP UNTIL THE DIAPHRAGM BUSHING CONTACTS THE STOP ON THE END OF THE BALL VALVE SHAFT AND TAKES ON THE END OF THE BALL VALVE SHAFT AND TAKES OVER THE FUEL REGULATION.OVER THE FUEL REGULATION.TO GET SMOOTH TRANSITION BETWEEN IDLE AND TO GET SMOOTH TRANSITION BETWEEN IDLE AND CRUISE POWER SETTING, THE CONSTANT EFFORT CRUISE POWER SETTING, THE CONSTANT EFFORT SPRING PRE-LOADS THE AIR DIAPHRAGM TO A NEUTRAL SPRING PRE-LOADS THE AIR DIAPHRAGM TO A NEUTRAL POSITION.POSITION.

A TYPICAL IDLE SYSTEMA TYPICAL IDLE SYSTEM

AUTOMATIC MIXTURE CONTROLAUTOMATIC MIXTURE CONTROL

INSTALLED IN PARALLEL WITH THE MANUAL INSTALLED IN PARALLEL WITH THE MANUAL MIXTURE CONTROL.MIXTURE CONTROL.UTILIZED A SEALED BELLOWS THAT MOVES A UTILIZED A SEALED BELLOWS THAT MOVES A REVERSE TAPERED NEEDLE TO VARY THE SIZE OF REVERSE TAPERED NEEDLE TO VARY THE SIZE OF AN AIR BLEED BETWEEN THE IMPACT AND AN AIR BLEED BETWEEN THE IMPACT AND VENTURI AIR CHAMBER.VENTURI AIR CHAMBER.THE BELLOW IS FILLED WITH HELIUM, WILL THE BELLOW IS FILLED WITH HELIUM, WILL EXPAND AND CONTRACT WITH CHANGE IN AIR EXPAND AND CONTRACT WITH CHANGE IN AIR DENSITY.DENSITY.AS AIRCRAFT CLIMBS / ASCENDS, AIR DENSITY AS AIRCRAFT CLIMBS / ASCENDS, AIR DENSITY DECREASES, BELLOW EXPAND.DECREASES, BELLOW EXPAND.THE EXPANSION PUSHES THE NEEDLE VALVE OFF THE EXPANSION PUSHES THE NEEDLE VALVE OFF ITS SEAT TO OPEN THE BLEED AIR PORT.ITS SEAT TO OPEN THE BLEED AIR PORT.THIS REDUCES THE PRESSURE DIFFERENTIAL THIS REDUCES THE PRESSURE DIFFERENTIAL ACROSS THE AIR DIAPHRAGM, WHICH PARTIALLY ACROSS THE AIR DIAPHRAGM, WHICH PARTIALLY CLOSES THE BALL VALVE.CLOSES THE BALL VALVE.

TYPICAL AUTOMATIC TYPICAL AUTOMATIC MIXTURE CONTROLMIXTURE CONTROL

FLOW DIVIDERFLOW DIVIDERMETERED FUEL FLOW FROM THE REGULATOR TO METERED FUEL FLOW FROM THE REGULATOR TO THE FLOW DIVIDER.THE FLOW DIVIDER.LOCATED ON TOP, CENTER OF AN ENGINE.LOCATED ON TOP, CENTER OF AN ENGINE.CONSIST OF A DIAPHRAGM OPERATED VALVE CONSIST OF A DIAPHRAGM OPERATED VALVE AND A SPRING.AND A SPRING.WHEN NO FUEL PRESSURE, COMBINATION OF WHEN NO FUEL PRESSURE, COMBINATION OF ATMOSPHERE AND SPRING PRESSURE HOLDS ATMOSPHERE AND SPRING PRESSURE HOLDS THE VALVE IN THE CLOSED POSITION.THE VALVE IN THE CLOSED POSITION.WHEN FUEL PRESSURE BUILDS ENOUGH TO WHEN FUEL PRESSURE BUILDS ENOUGH TO OVERCOME ATMOSPHERIC AND SPRING OVERCOME ATMOSPHERIC AND SPRING PRESSURE, VALVE OPENS AND ALLOWS FUEL PRESSURE, VALVE OPENS AND ALLOWS FUEL INTO THE FLOW DIVIDER.INTO THE FLOW DIVIDER.FUEL FLOWS THROUGH 1/8" STAINLESS STEEL FUEL FLOWS THROUGH 1/8" STAINLESS STEEL TUBING OUT TO EACH INJECTOR NOZZLE.TUBING OUT TO EACH INJECTOR NOZZLE.AN OUTLET ALSO PROVIDED FOR A PRESSURE AN OUTLET ALSO PROVIDED FOR A PRESSURE GAUGE IN THE COCKPIT, CALIBRATED IN POUND GAUGE IN THE COCKPIT, CALIBRATED IN POUND PER SQUARE INCH (PSI), GAL/HR OR LBS/HR.PER SQUARE INCH (PSI), GAL/HR OR LBS/HR.

PRESSURE READING AT THE FLOW DIVIDER PRESSURE READING AT THE FLOW DIVIDER INDICATE COLLECTIVE PRESSURE DROP ACROSS INDICATE COLLECTIVE PRESSURE DROP ACROSS ALL THE FUEL INJECTOR NOZZLE.ALL THE FUEL INJECTOR NOZZLE.THE GAUGE PRESSURE IS DIRECTLY THE GAUGE PRESSURE IS DIRECTLY PROPORTIONAL TO THE PRESSURE DROP PROPORTIONAL TO THE PRESSURE DROP CAUSED BY FUEL FLOW THROUGH THE NOZZLES.CAUSED BY FUEL FLOW THROUGH THE NOZZLES.AT ALL SPEED ABOVE IDLE, THE SMALL OPENING AT ALL SPEED ABOVE IDLE, THE SMALL OPENING IN THE NOZZLE RESTRICT THE AMOUNT OF FUEL IN THE NOZZLE RESTRICT THE AMOUNT OF FUEL THAT CAN FLOW INTO EACH CYLINDER.THAT CAN FLOW INTO EACH CYLINDER.THIS CAUSE A BACK PRESSURE TO BUILD UP IN THIS CAUSE A BACK PRESSURE TO BUILD UP IN THE METERED FUEL LINE, IN TURN INFLUENCES THE METERED FUEL LINE, IN TURN INFLUENCES THE FUEL METERING FORCE.THE FUEL METERING FORCE.BASED ON THIS, NOZZLES CONTROL FUEL BASED ON THIS, NOZZLES CONTROL FUEL PRESSURE WHEN ENGINE RPM IS ABOVE IDLE.PRESSURE WHEN ENGINE RPM IS ABOVE IDLE.

FLOW DIVIDERFLOW DIVIDER CONT. CONT.

TYPICAL FLOW DIVIDERTYPICAL FLOW DIVIDER

SPRINGSPRINGDIAPHRAGMDIAPHRAGM

DURING IDLE, FUEL FLOW THROUGH THE NOZZLE DURING IDLE, FUEL FLOW THROUGH THE NOZZLE IS INSUFFICIENT TO CREATE THE BACK PRESSURE IS INSUFFICIENT TO CREATE THE BACK PRESSURE REQUIRED FOR FUEL METERING.REQUIRED FOR FUEL METERING.THE COIL SPRING ON THE AIR SIDE OF THE THE COIL SPRING ON THE AIR SIDE OF THE DIAPHRAGM HOLDS THE FLOW DIVIDER VALVE DIAPHRAGM HOLDS THE FLOW DIVIDER VALVE CLOSED UNTIL METERED FUEL PRESSURE CLOSED UNTIL METERED FUEL PRESSURE BECOME SUFFICIENT TO OFFSET THE VALVE.BECOME SUFFICIENT TO OFFSET THE VALVE.WHEN METERED FUEL PRESSURE RAISED ENOUGH WHEN METERED FUEL PRESSURE RAISED ENOUGH TO OVERCOME SPRING TENSION, THE FLOW TO OVERCOME SPRING TENSION, THE FLOW DIVIDER OPENS AND EVENLY DISTRIBUTES FUEL DIVIDER OPENS AND EVENLY DISTRIBUTES FUEL TO THE CYLINDERS DURING LOW FUEL FLOW TO THE CYLINDERS DURING LOW FUEL FLOW CONDITION.CONDITION.AN ADDED BENEFIT, WHEN MIXTURE CONTROL AN ADDED BENEFIT, WHEN MIXTURE CONTROL PLACED IN IDLE-CUTOFF POSITION, THE SPRING PLACED IN IDLE-CUTOFF POSITION, THE SPRING FORCES THE DIVIDER VALVE DOWN, PROVIDES FORCES THE DIVIDER VALVE DOWN, PROVIDES POSITIVE FUEL CUT-OFF TO THE NOZZLE.POSITIVE FUEL CUT-OFF TO THE NOZZLE.REDUCE THE CHANCE OF VAPOR LOCK BY REDUCE THE CHANCE OF VAPOR LOCK BY TRAPPING FUEL IN THE INJECTOR LINES.TRAPPING FUEL IN THE INJECTOR LINES.

FLOW DIVIDERFLOW DIVIDER CONT. CONT.

INJECTOR NOZZLEINJECTOR NOZZLE USES AIR-BLEED TYPE NOZZLE, THREADED USES AIR-BLEED TYPE NOZZLE, THREADED

INTO THE CYLINDER HEAD NEAR THE INTAKE INTO THE CYLINDER HEAD NEAR THE INTAKE PORTS.PORTS.

BRASS BODY CONSTRUCTED WITH A BRASS BODY CONSTRUCTED WITH A METERING ORIFICE, AIR BLEED HOLE AND AN METERING ORIFICE, AIR BLEED HOLE AND AN EMULSION CHAMBER.EMULSION CHAMBER.

A FINE MESH METAL SCREEN AND PRESSED A FINE MESH METAL SCREEN AND PRESSED STEEL SHROUD SURROUND THE BRASS BODY STEEL SHROUD SURROUND THE BRASS BODY TO PREVENT CONTAMINATION.TO PREVENT CONTAMINATION.

TO EMULSIFY THE FUEL, THE FUEL NOZZLE TO EMULSIFY THE FUEL, THE FUEL NOZZLE USED ON SOME TURBOCHARGED ENGINE USED ON SOME TURBOCHARGED ENGINE INCLUDE AN EXTENSION THAT ALLOWS THE INCLUDE AN EXTENSION THAT ALLOWS THE NOZZLE TO RECEIVE UPPER DECK PRESSURE.NOZZLE TO RECEIVE UPPER DECK PRESSURE.

EACH NOZZLE INCORPORATES A CALIBRATED EACH NOZZLE INCORPORATES A CALIBRATED METERING ORIFICE OR JET TO PROVIDE A METERING ORIFICE OR JET TO PROVIDE A SPECIFIC FLOW RATE ±2%.SPECIFIC FLOW RATE ±2%.

THE JET SIZE IS DETERMINED BY THE FUEL THE JET SIZE IS DETERMINED BY THE FUEL INLET PRESSURE AND THE MAXIMUM FUEL INLET PRESSURE AND THE MAXIMUM FUEL FLOW REQUIRED BY THE ENGINE.FLOW REQUIRED BY THE ENGINE.

NOZZLES OF THE SAME TYPE ARE NOZZLES OF THE SAME TYPE ARE INTERCHANGEABLE BETWEEN ENGINE INTERCHANGEABLE BETWEEN ENGINE AND CYLINDER.AND CYLINDER.

IDENTIFICATION MARK STAMPED ON THE IDENTIFICATION MARK STAMPED ON THE HEX. FLAT ON THE NOZZLE OPPOSITE THE HEX. FLAT ON THE NOZZLE OPPOSITE THE AIR BLEED-HOLE, DENOTE THE SIZE OF AIR BLEED-HOLE, DENOTE THE SIZE OF THE JET, MARK WITH SINGLE LETTER.THE JET, MARK WITH SINGLE LETTER.

AS FUEL FLOWS INTO THE FUEL NOZZLE, IT AS FUEL FLOWS INTO THE FUEL NOZZLE, IT PASSES THROUGH THE METERING JET PASSES THROUGH THE METERING JET INTO EMULSION CHAMBER AND MIXED INTO EMULSION CHAMBER AND MIXED WITH AIR.WITH AIR.

INJECTOR NOZZLEINJECTOR NOZZLE

TYPICAL FUEL INJECTORTYPICAL FUEL INJECTOR

SINCE THE END OF THE NOZZLE IS EXPOSED SINCE THE END OF THE NOZZLE IS EXPOSED TO MANIFOLD PRESSURE ON NORMALLY TO MANIFOLD PRESSURE ON NORMALLY ASPIRATED ENGINE, WHICH IS LESS THAN ASPIRATED ENGINE, WHICH IS LESS THAN ATMOSPHERIC PRESSURE, AIR IS PULLED ATMOSPHERIC PRESSURE, AIR IS PULLED INTO THE NOZZLE THROUGH THE BLEED.INTO THE NOZZLE THROUGH THE BLEED.

AS FUEL MIXED WITH AIR IN THE EMULSION AS FUEL MIXED WITH AIR IN THE EMULSION CHAMBER, THE FUEL IS ATOMIZED.CHAMBER, THE FUEL IS ATOMIZED.

WITH TURBOCHARGED ENGINE MANIFOLD WITH TURBOCHARGED ENGINE MANIFOLD PRESSURE IS HIGHER THAN ATMOSPHERIC, PRESSURE IS HIGHER THAN ATMOSPHERIC, HIGH PRESSURE AIR FROM UPPER DECK IS HIGH PRESSURE AIR FROM UPPER DECK IS TAKEN FOR THE USED OF AIR BLEED.TAKEN FOR THE USED OF AIR BLEED.

WHEN INSTALLING THE FUEL NOZZLE, WHEN INSTALLING THE FUEL NOZZLE, ENSURE THE BLEED HOLE IS POINTING ENSURE THE BLEED HOLE IS POINTING UPWARD TO PREVENT FUEL DRAIN OUT OF UPWARD TO PREVENT FUEL DRAIN OUT OF THE NOZZLE OR ONTO THE ENGINE, WHEN THE NOZZLE OR ONTO THE ENGINE, WHEN ENGINE IS SHUT DOWN.ENGINE IS SHUT DOWN.

INJECTOR NOZZLE INJECTOR NOZZLE CONT.CONT.

IF AIR BLEED BECOME BLOCK/PLUGGED, THE IF AIR BLEED BECOME BLOCK/PLUGGED, THE OUTSIDE OF THE METERING JET WILL EXPOSED OUTSIDE OF THE METERING JET WILL EXPOSED TO MANIFOLD PRESSURE INSTEAD OF TO MANIFOLD PRESSURE INSTEAD OF ATMOSPHERIC PRESSURE.ATMOSPHERIC PRESSURE.

THIS INCREASE THE DIFFERENTIAL PRESSURE THIS INCREASE THE DIFFERENTIAL PRESSURE ACROSS THE NOZZLE METERING JET CAUSE ACROSS THE NOZZLE METERING JET CAUSE MORE FUEL TO FLOW THROUGH THE NOZZLE.MORE FUEL TO FLOW THROUGH THE NOZZLE.

THE REGULATOR UNIT DELIVERS A SET AMOUNT THE REGULATOR UNIT DELIVERS A SET AMOUNT OF FUEL TO THE FLOW DIVIDER AT A GIVEN OF FUEL TO THE FLOW DIVIDER AT A GIVEN POWER SETTING.POWER SETTING.

WITH CLOGGED AIR BLEED, IT WILL TAKE MORE WITH CLOGGED AIR BLEED, IT WILL TAKE MORE FUEL FROM THE OTHER NOZZLE, PROVIDING RICH FUEL FROM THE OTHER NOZZLE, PROVIDING RICH MIXTURE WHILE THE REST WITH LEAN MIXTURE.MIXTURE WHILE THE REST WITH LEAN MIXTURE.

A CLOGGED AIR BLEED CAUSE A LOW FUEL FLOW A CLOGGED AIR BLEED CAUSE A LOW FUEL FLOW INDICATION (FUEL PRESSURE GAUGE INDICATION (FUEL PRESSURE GAUGE CONNECTED TO THE FLOW DIVIDER).CONNECTED TO THE FLOW DIVIDER).

INJECTOR NOZZLE INJECTOR NOZZLE CONT.CONT.

RSA SYSTEM INSPECTION AND RSA SYSTEM INSPECTION AND MAINTENANCEMAINTENANCE

INSPECTION INCLUDED CHECKING ALL RSA FUEL INSPECTION INCLUDED CHECKING ALL RSA FUEL COMPONENTS FOR SECURITY.COMPONENTS FOR SECURITY.MOUNTING FLANGE FOR CRACKS.MOUNTING FLANGE FOR CRACKS.ANY LEAK FROM THE HOUSING.ANY LEAK FROM THE HOUSING.SECURITY ON ALL CONTROL LINKAGES AND FREE SECURITY ON ALL CONTROL LINKAGES AND FREE MOVEMENT.MOVEMENT.ANY ABNORMALITIES SUCH AS LEAK, BEND, KINK, ANY ABNORMALITIES SUCH AS LEAK, BEND, KINK, DISTORTION, OR INDICATION OF LEAKAGE.DISTORTION, OR INDICATION OF LEAKAGE.CHECK FLOW DIVIDER VENT HOLE FREE FROM CHECK FLOW DIVIDER VENT HOLE FREE FROM OBSTRUCTION.OBSTRUCTION.FUEL NOZZLES SHOULD BE CLEAN PERIODICALLY TO FUEL NOZZLES SHOULD BE CLEAN PERIODICALLY TO REMOVE ANY VARNISH OR CONTAMINANTS.REMOVE ANY VARNISH OR CONTAMINANTS.CLEANING BY SOAKING WITH APPROVED CLEANER CLEANING BY SOAKING WITH APPROVED CLEANER AND BLOW OUT WITH COMPRESS AIR.AND BLOW OUT WITH COMPRESS AIR.ONCE CLEAN IT’S GOOD TO DO FLOW COMPARISON.ONCE CLEAN IT’S GOOD TO DO FLOW COMPARISON.

INSPECTION AND MAINTENANCEINSPECTION AND MAINTENANCE cont. cont.

FLOW COMPARISON CHECK IS BY FLOW COMPARISON CHECK IS BY INSTALLED ALL NOZZLE AND PLACED INSTALLED ALL NOZZLE AND PLACED EQUAL SIZE CONTAINER UNDER IT.EQUAL SIZE CONTAINER UNDER IT.

BOOST PUMP ON, MIXTURE FULL RICH, BOOST PUMP ON, MIXTURE FULL RICH, AND ADVANCE THROTTLE.AND ADVANCE THROTTLE.

FILL CONTAINERS TILL HALF FULL AND FILL CONTAINERS TILL HALF FULL AND COMPARE LEVEL.COMPARE LEVEL.

ANY CONTAINER WITH SUBSTANTIAL LOW ANY CONTAINER WITH SUBSTANTIAL LOW LEVEL, CHECK RESTRICTION ON NOZZLE, LEVEL, CHECK RESTRICTION ON NOZZLE, SUPPLY LINE OR FLOW DIVIDER.SUPPLY LINE OR FLOW DIVIDER.

FIELD ADJUSTMENTFIELD ADJUSTMENTTWO TYPES OF ADJUSTMENT:TWO TYPES OF ADJUSTMENT:– IDLE MIXTURE.IDLE MIXTURE.– IDLE SPEED.IDLE SPEED.

IDLE MIXTURE – ADJUSTED ON IDLE MIXTURE – ADJUSTED ON MECHANICAL LINKAGE BY VARYING THE MECHANICAL LINKAGE BY VARYING THE LENGTH OF THE LINKAGE BETWEEN THE LENGTH OF THE LINKAGE BETWEEN THE TWO VALVES.TWO VALVES.IDLE SPEED – ADJUSTED BY TURNING THE IDLE SPEED – ADJUSTED BY TURNING THE SPRING LOADED ADJUSTMENT SCREW.SPRING LOADED ADJUSTMENT SCREW.ALL ADJUSTMENT ARE CARRIED OUT BY ALL ADJUSTMENT ARE CARRIED OUT BY RUNNING THE ENGINE AS PER RUNNING THE ENGINE AS PER MANUFACTURE STARTING CHECKLIST, MANUFACTURE STARTING CHECKLIST, ADJUST AS NECESSARY AND RECHECK ADJUST AS NECESSARY AND RECHECK FOR PROPER OPERATION. FOR PROPER OPERATION.

By changing By changing the length of the length of the adjusting the adjusting rod.rod.

IDLE SPEED AND MIXTURE IDLE SPEED AND MIXTURE ADJUSTMENTADJUSTMENT

Teledyne Teledyne conTinenTal conTinenTal

SySTeMSySTeM

TELEDYNE CONTINENTAL FUEL TELEDYNE CONTINENTAL FUEL INJECTION SYSTEMINJECTION SYSTEM

USES FUEL METERING FORCE ONLY TO USES FUEL METERING FORCE ONLY TO DETERMINE THE AMOUNT OF FUEL TO DETERMINE THE AMOUNT OF FUEL TO SEND TO THE INJECTOR NOZZLE.SEND TO THE INJECTOR NOZZLE.

SYSTEM HAS FOUR BASIC COMPONENTS:SYSTEM HAS FOUR BASIC COMPONENTS:

ENGINE-DRIVEN INJECTOR PUMP.ENGINE-DRIVEN INJECTOR PUMP.

A FUEL/AIR CONTROL UNIT.A FUEL/AIR CONTROL UNIT.

A FUEL MANIFOLD VALVE.A FUEL MANIFOLD VALVE.

INJECTOR NOZZLES.INJECTOR NOZZLES.

INJECTOR PUMPINJECTOR PUMPVANE-TYPE CONSTANT-DISPLACEMENT PUMP, VANE-TYPE CONSTANT-DISPLACEMENT PUMP, ENGINE DRIVEN BY A SPLINED SHAFT.ENGINE DRIVEN BY A SPLINED SHAFT.THE PUMP'S DRIVE SHAFT HAS A SHEAR SECTION THE PUMP'S DRIVE SHAFT HAS A SHEAR SECTION AND A LOOSE COUPLING TO PROTECT THE ENGINE AND A LOOSE COUPLING TO PROTECT THE ENGINE IN CASE OF PUMP FAILURE AND COMPENSATE FOR IN CASE OF PUMP FAILURE AND COMPENSATE FOR MISALIGNMENT BETWEEN THE PUMP AND THE MISALIGNMENT BETWEEN THE PUMP AND THE ENGINE DRIVE.ENGINE DRIVE.PRODUCE OUTPUT PRESSURE THAT VARIES WITH PRODUCE OUTPUT PRESSURE THAT VARIES WITH THE ENGINE SPEED.THE ENGINE SPEED.ADDITIONAL COMPONENTS :ADDITIONAL COMPONENTS :– VAPOR SEPARATOR CHAMBER.VAPOR SEPARATOR CHAMBER.– AN ADJUSTABLE ORIFICE AND RELIEF VALVE.AN ADJUSTABLE ORIFICE AND RELIEF VALVE.– A VAPOR EJECTOR.A VAPOR EJECTOR.– A BYPASS VALVEA BYPASS VALVE

A TYPICAL INJECTOR PUMP A TYPICAL INJECTOR PUMP

INJECTOR PUMPINJECTOR PUMP CONT. CONT.

THE FUEL ENTERS THE PUMP THROUGH THE VAPOR THE FUEL ENTERS THE PUMP THROUGH THE VAPOR SEPARATOR CHAMBER WHERE THE VAPOR IS SWIRLED SEPARATOR CHAMBER WHERE THE VAPOR IS SWIRLED OUT TO COLLECT IN THE TOP.OUT TO COLLECT IN THE TOP.SOME FUEL FROM THE PUMP OUTLET RETURN TO FUEL SOME FUEL FROM THE PUMP OUTLET RETURN TO FUEL TANK THROUGH THE VAPOR VENTURI OR JET PUMP TANK THROUGH THE VAPOR VENTURI OR JET PUMP (VAPOR EJECTOR).(VAPOR EJECTOR).THE VENTURI PRODUCES A LOW PRESSURE ATTRACTS THE VENTURI PRODUCES A LOW PRESSURE ATTRACTS THE VAPORS TO RETURN TO THE TANK.THE VAPORS TO RETURN TO THE TANK.BY INCORPORATING A VARIABLE ORIFICE, FUEL BY INCORPORATING A VARIABLE ORIFICE, FUEL PRESSURE PROPORTIONAL TO ENGINE SPEED IS PRESSURE PROPORTIONAL TO ENGINE SPEED IS PROVIDED.PROVIDED.THE SIZE OF THE ORIFICE WILL DETERMINE THE THE SIZE OF THE ORIFICE WILL DETERMINE THE PRESSURE, SIZE INCREASE THE OUTPUT PRESSURE PRESSURE, SIZE INCREASE THE OUTPUT PRESSURE WILL DECREASE AND VICE-VERSA.WILL DECREASE AND VICE-VERSA.SYSTEM WORKS WELL FOR FLOWS AT CRUISE AND SYSTEM WORKS WELL FOR FLOWS AT CRUISE AND HIGH POWER RANGE.HIGH POWER RANGE.AT IDLING OR BELOW CRUISE, FUEL FLOW IS SO LOW AT IDLING OR BELOW CRUISE, FUEL FLOW IS SO LOW THAT THE ORIFICE DOES NOT PRODUCE ENOUGH THAT THE ORIFICE DOES NOT PRODUCE ENOUGH RESTRICTION TO MAINTAIN CONSTANT OUTPUT RESTRICTION TO MAINTAIN CONSTANT OUTPUT PRESSURE (THE ORIFICE HAS NO EFFECT).PRESSURE (THE ORIFICE HAS NO EFFECT).

ADJUSTABLE PRESSURE RELIEF VALVE, INSTALLED ADJUSTABLE PRESSURE RELIEF VALVE, INSTALLED DOWNSTREAM FROM THE ORIFICE, DETERMINED THE DOWNSTREAM FROM THE ORIFICE, DETERMINED THE CONSTANT OUTPUT PRESSURECONSTANT OUTPUT PRESSURE..AT HIGH POWER SETTING THE RELIEF VALVE OFF ITS AT HIGH POWER SETTING THE RELIEF VALVE OFF ITS SEAT AND THE ORIFICE TAKES OVER TO MAINTAIN SEAT AND THE ORIFICE TAKES OVER TO MAINTAIN CONSTANT PRESSURE OUTPUT.CONSTANT PRESSURE OUTPUT.BYPASS VALVE ALLOW FUEL FROM AUXILIARY PUMP BYPASS VALVE ALLOW FUEL FROM AUXILIARY PUMP (BOOST PUMP) FOR ENGINE STARTING AND (BOOST PUMP) FOR ENGINE STARTING AND OPERATION SHOULD THE INJECTOR PUMP OPERATION SHOULD THE INJECTOR PUMP MALFUNCTION.MALFUNCTION.AS ENGINE PUMP PRESSURE BECOMES HIGHER OR AS ENGINE PUMP PRESSURE BECOMES HIGHER OR EXCEEDS THE BOOST PUMP PRESSURE, THE BYPASS EXCEEDS THE BOOST PUMP PRESSURE, THE BYPASS CHECK VALVE CLOSED AND ENGINE PUMP TAKES CHECK VALVE CLOSED AND ENGINE PUMP TAKES OVER.OVER.WITH TURBOCHARGED ENGINE, AS THROTTLE IS WITH TURBOCHARGED ENGINE, AS THROTTLE IS OPENED OR ADVANCED RAPIDLY THE INJECTOR PUMP OPENED OR ADVANCED RAPIDLY THE INJECTOR PUMP ACCELERATES AND SUPPLIES ADDITIONAL FUEL ACCELERATES AND SUPPLIES ADDITIONAL FUEL BEFORE THE TURBOCHARGER COULD REALLY BEFORE THE TURBOCHARGER COULD REALLY RESPONSE OR SPEED UP.RESPONSE OR SPEED UP.


THE IMBALANCE CAUSES MIXTURE TO TEMPORARILY THE IMBALANCE CAUSES MIXTURE TO TEMPORARILY BECOME TOO RICH CAUSING ENGINE TO FALTER.BECOME TOO RICH CAUSING ENGINE TO FALTER.AN ALTITUDE COMPENSATING BELLOWS (ANEROID) AN ALTITUDE COMPENSATING BELLOWS (ANEROID) CONTROL THE SIZE OF THE METERING ORIFICE.CONTROL THE SIZE OF THE METERING ORIFICE.THE ANEROID IS EXPOSED TO THE UPPER DECK THE ANEROID IS EXPOSED TO THE UPPER DECK PRESSURE (TURBOCHARGER DISCHARGE PRESSURE).PRESSURE (TURBOCHARGER DISCHARGE PRESSURE).AS THROTTLE IS OPEN RAPIDLY THE UPPER DECK AS THROTTLE IS OPEN RAPIDLY THE UPPER DECK PRESSURE FLUCTUATES OR LOW, AND THE BELLOWS PRESSURE FLUCTUATES OR LOW, AND THE BELLOWS EXPANDED, INCREASED THE ORIFICE SIZE.EXPANDED, INCREASED THE ORIFICE SIZE.IN RESPOND TO THE SUDDEN OPENING, HOLDS THE IN RESPOND TO THE SUDDEN OPENING, HOLDS THE ORIFICE OPEN, SO THAT PUMP OUTPUT DOES NOT ORIFICE OPEN, SO THAT PUMP OUTPUT DOES NOT INCREASE UNTIL THE VOLUME OF AIR FLOWING INTO INCREASE UNTIL THE VOLUME OF AIR FLOWING INTO THE ENGINE INCREASES.THE ENGINE INCREASES.AS THE TURBOCHARGER SPEED BUILDS UP, UPPER AS THE TURBOCHARGER SPEED BUILDS UP, UPPER DECK PRESSURE INCREASES CAUSES THE BELLOWS DECK PRESSURE INCREASES CAUSES THE BELLOWS TO CONTRACT AND THE ORIFICE BECOME SMALLER TO CONTRACT AND THE ORIFICE BECOME SMALLER OR MORE RESTRICTIVE TO INCREASE THE FUEL FLOW OR MORE RESTRICTIVE TO INCREASE THE FUEL FLOW AND PRESSURE OUTPUT TO THE ENGINE.AND PRESSURE OUTPUT TO THE ENGINE.


TYPICAL INJECTOR PUMP WITH TYPICAL INJECTOR PUMP WITH ANEROID CONTROLLED RESTRICTORANEROID CONTROLLED RESTRICTOR

PUMP’S DRIVE SHAFT HAS A SHEAR PUMP’S DRIVE SHAFT HAS A SHEAR SECTION TO PROTECT THE ENGINE IN SECTION TO PROTECT THE ENGINE IN CASE OF PUMP FAILS.CASE OF PUMP FAILS.

MOST PUMP UTILIZED LOOSE COUPLING MOST PUMP UTILIZED LOOSE COUPLING TO COMPENSATE FOR SLIGHT TO COMPENSATE FOR SLIGHT MISALIGNMENT BETWEEN PUMP AND MISALIGNMENT BETWEEN PUMP AND ENGINE DRIVEENGINE DRIVE


FUEL / AIR CONTROL UNITFUEL / AIR CONTROL UNITCONSISTS OF THE THROTTLE VALVE (AIR CONSISTS OF THE THROTTLE VALVE (AIR THROTTLE ASSEMBLY) THAT DOES NOT THROTTLE ASSEMBLY) THAT DOES NOT USE VENTURI, CONTROLS THE AMOUNT OF USE VENTURI, CONTROLS THE AMOUNT OF AIR ENTERING THE ENGINE.AIR ENTERING THE ENGINE.AN ADJUSTABLE LINKAGE CONNECTS THE AN ADJUSTABLE LINKAGE CONNECTS THE AIR THROTTLE VALVE WITH THE THROTTLE AIR THROTTLE VALVE WITH THE THROTTLE FUEL VALVE (FUEL CONTROL ASSEMBLY).FUEL VALVE (FUEL CONTROL ASSEMBLY).THE FUEL CONTROL ASSEMBLY MADE OF THE FUEL CONTROL ASSEMBLY MADE OF BRONZE, HOUSES THE MIXTURE VALVE BRONZE, HOUSES THE MIXTURE VALVE AND THE FUEL METERING VALVE.AND THE FUEL METERING VALVE.MIXTURE AND FUEL METERING VALVES MIXTURE AND FUEL METERING VALVES ARE OF ROTARY-TYPE VALVES MADE OF ARE OF ROTARY-TYPE VALVES MADE OF STAINLESS STEEL, ROTATED IN OIL-STAINLESS STEEL, ROTATED IN OIL-IMPREGNATED BUSHINGS.IMPREGNATED BUSHINGS.

TYPICAL FUEL CONTROL TYPICAL FUEL CONTROL ASEMBLYASEMBLY

FUEL / AIR CONTROL UNIT FUEL / AIR CONTROL UNIT cont.cont.

THE END OF EACH VALVE ROTATES AGAINST A THE END OF EACH VALVE ROTATES AGAINST A FIXED METERING PLUG IN THE CENTER OF THE FIXED METERING PLUG IN THE CENTER OF THE FUEL CONTROL UNIT.FUEL CONTROL UNIT.THE METERING PLUG MADE OF BRONZE, THE METERING PLUG MADE OF BRONZE, CONTAINS A FUEL METERING JET WHICH CONTAINS A FUEL METERING JET WHICH METERS THE FUEL FLOW TO THE ENGINE.METERS THE FUEL FLOW TO THE ENGINE.THE METERING PLUG HAS ONE PASSAGE THAT THE METERING PLUG HAS ONE PASSAGE THAT CONNECTS THE FUEL INLET WITH THE FUEL CONNECTS THE FUEL INLET WITH THE FUEL RETURN OUTLET.RETURN OUTLET.ANOTHER ONE PASSAGE CONNECTS THE ANOTHER ONE PASSAGE CONNECTS THE MIXTURE CONTROL VALVE CHAMBER WITH MIXTURE CONTROL VALVE CHAMBER WITH FUEL METERING VALVE CHAMBER.FUEL METERING VALVE CHAMBER.THE MIXTURE VALVE ACTS AS A VARIABLE THE MIXTURE VALVE ACTS AS A VARIABLE SELECTOR VALVE WHICH DIRECTS FUEL TO SELECTOR VALVE WHICH DIRECTS FUEL TO EITHER METERING JET OR BACK TO THE FUEL EITHER METERING JET OR BACK TO THE FUEL PUMP.PUMP.

TYPICAL FUEL/AIR TYPICAL FUEL/AIR CONTROL UNITCONTROL UNIT

FUEL FLOW PAST THE MIXTURE VALVE AND FLOW FUEL FLOW PAST THE MIXTURE VALVE AND FLOW THROUGH THE METERING JET.THROUGH THE METERING JET.THE AMOUNT OF FUEL FLOW OUT OF THE MAIN THE AMOUNT OF FUEL FLOW OUT OF THE MAIN METERING JET DETERMINED BY THE POSITION OF THE METERING JET DETERMINED BY THE POSITION OF THE FUEL METERING VALVE.FUEL METERING VALVE.THE VALVE PLATE USED WITH THE FUEL METERING THE VALVE PLATE USED WITH THE FUEL METERING VALVE PROPORTIONATELY OPENED THE OUTLET OF VALVE PROPORTIONATELY OPENED THE OUTLET OF THE MAIN JET AS THE THROTTLE IS ADVANCED.THE MAIN JET AS THE THROTTLE IS ADVANCED.EXAMPLE : AT LOW POWER SETTING, ONLY SMALL EXAMPLE : AT LOW POWER SETTING, ONLY SMALL PORTION OF THE MAIN METERING JET IS OPENED.PORTION OF THE MAIN METERING JET IS OPENED.AS THE THROTTLE IS ADVANCED MORE OF THE MAIN AS THE THROTTLE IS ADVANCED MORE OF THE MAIN METERING JET IS UNCOVERED OR OPENED TO PROVIDE METERING JET IS UNCOVERED OR OPENED TO PROVIDE ADDITIONAL FUEL.ADDITIONAL FUEL.THE FUEL METERING VALVE OPERATED WITH CONTROL THE FUEL METERING VALVE OPERATED WITH CONTROL ARM CONNECTED TO THE COCKPIT THROTTLE LEVER, ARM CONNECTED TO THE COCKPIT THROTTLE LEVER, MEANING THE THROTTLE LEVER CONTROLS BOTH THE MEANING THE THROTTLE LEVER CONTROLS BOTH THE THROTTLE AIR VALVE AND THE FUEL METERING VALVE.THROTTLE AIR VALVE AND THE FUEL METERING VALVE.THE SAME TYPE OF DEVICE USED IN FLOW DIVIDER OF THE SAME TYPE OF DEVICE USED IN FLOW DIVIDER OF RSA SYSTEM.RSA SYSTEM.

FUEL / AIR CONTROL UNITFUEL / AIR CONTROL UNIT cont. cont.

THROTTLE AIR VALVE THROTTLE AIR VALVE AND FUEL METERING AND FUEL METERING

VALVEVALVE

FUEL MANIFOLD VALVEFUEL MANIFOLD VALVE

FUEL FROM METERING VALVE, THROUGH FUEL FROM METERING VALVE, THROUGH FLEXIBLE HOSE TO FUEL MANIFOLD VALVE.FLEXIBLE HOSE TO FUEL MANIFOLD VALVE.PURPOSE OF THE MANIFOLD VALVE PURPOSE OF THE MANIFOLD VALVE (DISTRIBUTION VALVE) IS TO EVENLY (DISTRIBUTION VALVE) IS TO EVENLY DISTRIBUTE FUEL TO ALL CYLINDERS.DISTRIBUTE FUEL TO ALL CYLINDERS.POSITIVE FUEL SHUTOFF TO THE NOZZLES WHEN POSITIVE FUEL SHUTOFF TO THE NOZZLES WHEN THE MIXTURE CONTROL IN THE IDLE-CUT-OFF THE MIXTURE CONTROL IN THE IDLE-CUT-OFF POSITION.POSITION.LOCATED ON TOP OF THE ENGINE.LOCATED ON TOP OF THE ENGINE.CONSIST OF:CONSIST OF:– FUEL INLET,FUEL INLET,– DIAPHRAGM CHAMBER,DIAPHRAGM CHAMBER,– A POPPET VALVE, ANDA POPPET VALVE, AND– SEVERAL OUTLET PORTS. SEVERAL OUTLET PORTS.

WHEN THE FUEL PRESSURE SUPPLIED BY THE WHEN THE FUEL PRESSURE SUPPLIED BY THE METERING VALVE IS SUFFICIENT, THE DIAPHRAGM METERING VALVE IS SUFFICIENT, THE DIAPHRAGM IN THE MANIFOLD VALVE IS FORCED UP TO LIFT IN THE MANIFOLD VALVE IS FORCED UP TO LIFT THE CUTOFF VALVE OFF ITS SEAT.THE CUTOFF VALVE OFF ITS SEAT.A SPRING-LOADED POPPET VALVE WITHIN THE A SPRING-LOADED POPPET VALVE WITHIN THE CUTOFF VALVE STAYS ON ITS SEAT, BLOCKING CUTOFF VALVE STAYS ON ITS SEAT, BLOCKING FUEL FLOW.FUEL FLOW.AS THE FUEL PRESSURE BUILDS ENOUGH TO AS THE FUEL PRESSURE BUILDS ENOUGH TO COMPLETELY OFF-SEAT THE CUTOFF VALVE, THE COMPLETELY OFF-SEAT THE CUTOFF VALVE, THE POPPET VALVE IS FORCED OPEN ALLOWING FUEL POPPET VALVE IS FORCED OPEN ALLOWING FUEL TO FLOW TO THE NOZZLES.TO FLOW TO THE NOZZLES.THE OPPOSITION BY THE POPPET VALVE THE OPPOSITION BY THE POPPET VALVE ENSURES A CONSTANT FUEL PRESSURE ENSURES A CONSTANT FUEL PRESSURE BETWEEN THE MAIN METERING JET AND BETWEEN THE MAIN METERING JET AND MANIFOLD VALVE FOR CONSISTENT METERING AT MANIFOLD VALVE FOR CONSISTENT METERING AT IDLE.IDLE.

FUEL MANIFOLD VALVE FUEL MANIFOLD VALVE cont.cont.

FUEL MANIFOLD VALVEFUEL MANIFOLD VALVE

ABOVE IDLE, FUEL PRESSURE HOLDS THE CUT-ABOVE IDLE, FUEL PRESSURE HOLDS THE CUT-OFF AND POPPET VALVES FULLY OPEN AND FUEL OFF AND POPPET VALVES FULLY OPEN AND FUEL PRESSURE IS MAINTAINED DUE TO THE PRESSURE IS MAINTAINED DUE TO THE RESTRICTION IN EACH INJECTOR NOZZLE RESTRICTION IN EACH INJECTOR NOZZLE WHEN THE MIXTURE CONTROL IS PLACED IN THE WHEN THE MIXTURE CONTROL IS PLACED IN THE IDLE-CUT-OFF POSITION, FUEL PRESSURE TO THE IDLE-CUT-OFF POSITION, FUEL PRESSURE TO THE MANIFOLD VALVE DROPS AND SPRING TENSION MANIFOLD VALVE DROPS AND SPRING TENSION CLOSES THE CUTOFF VALVE TO POSITIVELY CLOSES THE CUTOFF VALVE TO POSITIVELY SHUT-OFF THE FUEL AND TRAPS FUEL IN THE SHUT-OFF THE FUEL AND TRAPS FUEL IN THE SUPPLY LINES LEADING TO THE INJECTOR SUPPLY LINES LEADING TO THE INJECTOR NOZZLES.NOZZLES.THE CHAMBER ABOVE THE DIAPHRAGM IS THE CHAMBER ABOVE THE DIAPHRAGM IS VENTED TO AMBIENT AIR PRESSURE TO ALLOW VENTED TO AMBIENT AIR PRESSURE TO ALLOW UNRESTRICTED OR FREE VALVE MOVEMENT.UNRESTRICTED OR FREE VALVE MOVEMENT.THE FUEL MANIFOLD VALVES ARE POSITIONED THE FUEL MANIFOLD VALVES ARE POSITIONED WITH THE VENT OPENING TO THE SIDE OR THE WITH THE VENT OPENING TO THE SIDE OR THE REAR TO PREVENT RAM AIR FROM ENTERING THE REAR TO PREVENT RAM AIR FROM ENTERING THE AIR CHAMBER, CAUSING AIR FLUCTUATION AIR CHAMBER, CAUSING AIR FLUCTUATION ABOVE THE DIAPHRAGMABOVE THE DIAPHRAGM..

FUEL MANIFOLD VALVE FUEL MANIFOLD VALVE cont.cont.

INJECTION NOZZLESINJECTION NOZZLESAIR BLEED TYPE NOZZLES THREADED INTO THE AIR BLEED TYPE NOZZLES THREADED INTO THE CYLINDERS HEAD NEAR THE INTAKE PORTS.CYLINDERS HEAD NEAR THE INTAKE PORTS.NOZZLE OF BRASS BODY CONSTRUCTED WITH NOZZLE OF BRASS BODY CONSTRUCTED WITH METERING ORIFICE, MULTIPLE AIR BLEED HOLES METERING ORIFICE, MULTIPLE AIR BLEED HOLES AND AN EMULSION CHAMBER.AND AN EMULSION CHAMBER.A FINE MESH SCREEN AND PRESSED STEEL A FINE MESH SCREEN AND PRESSED STEEL SHROUD SURROUND THE BRASS BODY TO SHROUD SURROUND THE BRASS BODY TO PREVENT CONTAMINANTS FROM ENTERING THE PREVENT CONTAMINANTS FROM ENTERING THE BLEED HOLES.BLEED HOLES.EACH NOZZLE IS INCORPORATES WITH A EACH NOZZLE IS INCORPORATES WITH A CALIBRATED METERING ORIFICE OR JET TO CALIBRATED METERING ORIFICE OR JET TO PROVIDE A SPECIFIC FLOW RATE.PROVIDE A SPECIFIC FLOW RATE.THREE DIFFERENT SIZES OF METERING JET.THREE DIFFERENT SIZES OF METERING JET.THE JET SIZE DETERMINED BY THE FUEL INLET THE JET SIZE DETERMINED BY THE FUEL INLET PRESSURE AND THE MAXIMUM FUEL FLOW PRESSURE AND THE MAXIMUM FUEL FLOW REQUIRED BY THE ENGINE.REQUIRED BY THE ENGINE.

TYPICAL TELEDYNE-TYPICAL TELEDYNE-CONTINENTAL FUEL INJECTORCONTINENTAL FUEL INJECTOR

EMULSION EMULSION CHAMBERCHAMBER

SIZE IDENTIFIED BY MARK STAMPED ON THE HEX SIZE IDENTIFIED BY MARK STAMPED ON THE HEX FLAT OF THE NOZZLE WITH A SINGLE LETTER.FLAT OF THE NOZZLE WITH A SINGLE LETTER.EXAMPLE:-EXAMPLE:-A - SIZE WILL PROVIDE A SPECIFIC AMOUNT OF A - SIZE WILL PROVIDE A SPECIFIC AMOUNT OF FUEL.FUEL.B - SIZE PROVIDE ONE-HALF GALLON MORE FUEL B - SIZE PROVIDE ONE-HALF GALLON MORE FUEL PER/HOUR THAN A-SIZE WITH SAME PRESSURE.PER/HOUR THAN A-SIZE WITH SAME PRESSURE.C - SIZE PROVIDE THE LARGEST METERING JET AND C - SIZE PROVIDE THE LARGEST METERING JET AND A FULL GALLON PER HOUR MORE THAN A-SIZE A FULL GALLON PER HOUR MORE THAN A-SIZE WITH SAME PRESSURE.WITH SAME PRESSURE.THE ENGINE IS CALIBRATED DURING ITS MFG. RUN-THE ENGINE IS CALIBRATED DURING ITS MFG. RUN-UP AND PROPER SIZE NOZZLE IS INSTALLED.UP AND PROPER SIZE NOZZLE IS INSTALLED.INJECTOR NOZZLE SHOULD NEVER BE SIMPLY INJECTOR NOZZLE SHOULD NEVER BE SIMPLY CHANGED WITHOUT FIRST ESTABLISHED THE CHANGED WITHOUT FIRST ESTABLISHED THE PROPER SIZE FOR THE PARTICULAR ENGINE TYPE. PROPER SIZE FOR THE PARTICULAR ENGINE TYPE. AS THE FUEL FLOWS THROUGH THE METERING JET, AS THE FUEL FLOWS THROUGH THE METERING JET, IT ENTERS AN EMULSION CHAMBER TO MIX WITH IT ENTERS AN EMULSION CHAMBER TO MIX WITH AIR.AIR.

INJECTION NOZZLES INJECTION NOZZLES cont.cont.

THE ENGINE IS CALIBRATED DURING ITS THE ENGINE IS CALIBRATED DURING ITS MANUFACTURER RUN-UP AND PROPER SIZE MANUFACTURER RUN-UP AND PROPER SIZE NOZZLE IS INSTALLED AND SIZE SHOULD NOT NOZZLE IS INSTALLED AND SIZE SHOULD NOT BE CHANGE.BE CHANGE.THE END OF THE INJECTOR NOZZLE IS THE END OF THE INJECTOR NOZZLE IS EXPOSED TO MANIFOLD PRESSURE, WHICH IS EXPOSED TO MANIFOLD PRESSURE, WHICH IS LESS THAN ATMOSPHERIC PRESSURE (ON LESS THAN ATMOSPHERIC PRESSURE (ON NORMALLY ASPIRATED ENGINE), SO AIR IS NORMALLY ASPIRATED ENGINE), SO AIR IS PULLED INTO THE NOZZLE THROUGH THE PULLED INTO THE NOZZLE THROUGH THE BLEED AIR.BLEED AIR.THE AIR AND FUEL MIX IN THE EMULSION THE AIR AND FUEL MIX IN THE EMULSION CHAMBER AND FUEL IS ATOMIZED.CHAMBER AND FUEL IS ATOMIZED.ON A TURBOCHARGED ENGINE THE MANIFOLD ON A TURBOCHARGED ENGINE THE MANIFOLD PRESSURE OFTEN EXCEEDS THE PRESSURE OFTEN EXCEEDS THE ATMOSPHERIC PRESSURE SO HIGH PRESSURE ATMOSPHERIC PRESSURE SO HIGH PRESSURE AIR SOURCE MUST BE USED FOR THE AIR AIR SOURCE MUST BE USED FOR THE AIR BLEED.BLEED.

INJECTION NOZZLES INJECTION NOZZLES cont.cont.

THE HIGH AIR PRESSURE IS TAKEN FROM THE THE HIGH AIR PRESSURE IS TAKEN FROM THE TURBOCHARGER SIDE OF THE THROTTLE TURBOCHARGER SIDE OF THE THROTTLE VALVE OR UPPER DECK.VALVE OR UPPER DECK.INJECTOR NOZZLES COME IN DIFFERENT INJECTOR NOZZLES COME IN DIFFERENT STYLES TO SUIT ENGINE MODELS, SUCH AS STYLES TO SUIT ENGINE MODELS, SUCH AS LONG NOZZLE TO INJECT FUEL FURTHER LONG NOZZLE TO INJECT FUEL FURTHER INTO THE INTAKE CHAMBER.INTO THE INTAKE CHAMBER.SOME WITH SHORT NOZZLES DESIGN FOR ITS SOME WITH SHORT NOZZLES DESIGN FOR ITS ENGINE BEST PERFORMANCE.ENGINE BEST PERFORMANCE.BY THE WAY, THE DIFFERENCE IN BY THE WAY, THE DIFFERENCE IN APPEARANCE DO NOT CHANGED THE SYSTEM APPEARANCE DO NOT CHANGED THE SYSTEM METHOD.METHOD.

INJECTION NOZZLESINJECTION NOZZLES cont. cont.

INSPECTION AND MAINTENANCEINSPECTION AND MAINTENANCE

AT 100 HRS, CHECK ALL FUEL COMPONENTS FOR AT 100 HRS, CHECK ALL FUEL COMPONENTS FOR SECURITY AND INTEGRITY.SECURITY AND INTEGRITY.ALL LINES CHECK FOR CHAFING AND LEAKING AS ALL LINES CHECK FOR CHAFING AND LEAKING AS EVIDENCE BY FUEL STAIN.EVIDENCE BY FUEL STAIN.IMPORTANT NOTE, ALL FUEL LINES IMPORTANT NOTE, ALL FUEL LINES MANUFACTURED TO THE SAME LENGTH TO MANUFACTURED TO THE SAME LENGTH TO ENSURE SAME FUEL QUANTITY AND PRESSURE ENSURE SAME FUEL QUANTITY AND PRESSURE AND CANNOT BE ALTERED.AND CANNOT BE ALTERED.THROTTLE LINKAGE CHECK FOR FREE MOVEMENT, THROTTLE LINKAGE CHECK FOR FREE MOVEMENT, WEAR AND LUBRICATE AS REQUIRED.WEAR AND LUBRICATE AS REQUIRED.NOZZLE MAINTENANCE TYPICALLY CONSISTS OF NOZZLE MAINTENANCE TYPICALLY CONSISTS OF SOAKING IN ACETONE OR LACQUER THINNER AND SOAKING IN ACETONE OR LACQUER THINNER AND CLEARING OUT BY CLEAN DRY AIR, TYPICALLY AT CLEARING OUT BY CLEAN DRY AIR, TYPICALLY AT INTERVAL OF 100 AND 300 HOURS.INTERVAL OF 100 AND 300 HOURS.

DO NOT USE WIRE, DRILLS OR OTHER TOOLS TO DO NOT USE WIRE, DRILLS OR OTHER TOOLS TO CLEAR OUT ORIFICE OBSTRUCTIONS.CLEAR OUT ORIFICE OBSTRUCTIONS.

CLOGGED NOZZLE EVIDENCE BY STAIN AROUND CLOGGED NOZZLE EVIDENCE BY STAIN AROUND NOZZLE DUE TO FUEL PRESSURE BACK FLOW.NOZZLE DUE TO FUEL PRESSURE BACK FLOW.

CLOGGED NOZZLE THAT CANNOT BE CLEAR CLOGGED NOZZLE THAT CANNOT BE CLEAR TYPICALLY RECOMMENDED TO BE REPLACED.TYPICALLY RECOMMENDED TO BE REPLACED.

ALSO INSPECT FUEL MANIFOLD TO VERIFY VENT ALSO INSPECT FUEL MANIFOLD TO VERIFY VENT HOLE IS FREE OF OBSTRUCTION.HOLE IS FREE OF OBSTRUCTION.

PLUGGED HOLE CAUSE PRESSURE ACTING ON PLUGGED HOLE CAUSE PRESSURE ACTING ON ONE SIDE OF DIAPHRAGM WILL NOT VARY WITH ONE SIDE OF DIAPHRAGM WILL NOT VARY WITH CHANGE IN ALTITUDE AND DIVIDER WILL NOT CHANGE IN ALTITUDE AND DIVIDER WILL NOT OPEN THE CORRECT AMOUNT.OPEN THE CORRECT AMOUNT.

INSPECTION AND MAINTENANCEINSPECTION AND MAINTENANCE

FIELD ADJUSTMENTSFIELD ADJUSTMENTSTWO TYPES OF FIELD ADJUSTMENT:TWO TYPES OF FIELD ADJUSTMENT:IDLE MIXTURE.IDLE MIXTURE.– IDLE CUT-OFF, OBSERVE TACHOMETER – IDLE CUT-OFF, OBSERVE TACHOMETER –

RPM INCREASES SLIGHTLY BEFORE DROPS RPM INCREASES SLIGHTLY BEFORE DROPS OFF RAPIDLY.OFF RAPIDLY.

– MANIFOLD PRESSURE GAUGE – MANIFOLD MANIFOLD PRESSURE GAUGE – MANIFOLD PRESSURE DECREASING BEFORE ENGINE PRESSURE DECREASING BEFORE ENGINE CEASE FIRE.CEASE FIRE.

– TO INCREASE FUEL FLOW, CONNECTING TO INCREASE FUEL FLOW, CONNECTING LINKAGE NUT COUNTER CLOCKWISE.LINKAGE NUT COUNTER CLOCKWISE.

– TO DECREASE FUEL FLOW – CLOCKWISE.TO DECREASE FUEL FLOW – CLOCKWISE.IDLE SPEED. IDLE SPEED. – INCREASE – CLOCKWISE.INCREASE – CLOCKWISE.– DECREASE - COUNTER CLOCKWISE. DECREASE - COUNTER CLOCKWISE.

ADJUSTMENT OF IDLE ADJUSTMENT OF IDLE MIXTURE AND IDLE SPEEDMIXTURE AND IDLE SPEED

ONCE IDLE SPEED AND MIXTURE PROPERLY SET, ONCE IDLE SPEED AND MIXTURE PROPERLY SET, YOU SHOULD CHECK LOW AND HIGH METERED YOU SHOULD CHECK LOW AND HIGH METERED FUEL PRESSURE.FUEL PRESSURE.

CHECK BY CONNECTING CALIBRATED FUEL CHECK BY CONNECTING CALIBRATED FUEL PRESSURE GAUGE INTO A T-FITTING IN THE FUEL PRESSURE GAUGE INTO A T-FITTING IN THE FUEL LINES.LINES.

LOW METERED FUEL PRESSURE CAN BE ADJUST LOW METERED FUEL PRESSURE CAN BE ADJUST AT THE RELIEF VALVE.AT THE RELIEF VALVE.

HIGH METERED FUEL PRESSURE CAN BE ADJUST HIGH METERED FUEL PRESSURE CAN BE ADJUST AT THE ORIFICE IN THE FUEL PUMP RETURN LINE.AT THE ORIFICE IN THE FUEL PUMP RETURN LINE.

MAY HAVE TO RECHECK IDLE SPEED AND IDLE MAY HAVE TO RECHECK IDLE SPEED AND IDLE MIXTURE AFTER METERED FUEL PRESSURE MIXTURE AFTER METERED FUEL PRESSURE CHECK.CHECK.

FIELD ADJUSTMENTS FIELD ADJUSTMENTS cont.cont.

FUEL SYSTEM COMPONENTS AND FUEL SYSTEM COMPONENTS AND ADJUSTMENT PROCEDURES VARY ADJUSTMENT PROCEDURES VARY BETWEEN NORMALLY ASPIRATED AND BETWEEN NORMALLY ASPIRATED AND TURBOCHARGED ENGINE.TURBOCHARGED ENGINE.

ALWAYS FOLLOW MANUFACTURER ALWAYS FOLLOW MANUFACTURER INSTRUCTION.INSTRUCTION.

AFTER ALL ADJUSTMENT COMPLETED, AFTER ALL ADJUSTMENT COMPLETED, PREPARE AIRCRAFT FOR A FLIGHT TEST TO PREPARE AIRCRAFT FOR A FLIGHT TEST TO VERIFY HIGH METERED FUEL PRESSURE VERIFY HIGH METERED FUEL PRESSURE THAT CAN BE OBSERVED BETTER ON THAT CAN BE OBSERVED BETTER ON AIRCRAFT’S OWN FUEL FLOW GAUGE.AIRCRAFT’S OWN FUEL FLOW GAUGE.

FIELD ADJUSTMENTS FIELD ADJUSTMENTS cont.cont.

FUEL INJECTION SCHEMATIC FOR A FUEL INJECTION SCHEMATIC FOR A TYPICAL NORMALLY ASPIRATED ENGINETYPICAL NORMALLY ASPIRATED ENGINE

FUEL INJECTION SCHEMATIC FOR A FUEL INJECTION SCHEMATIC FOR A TYPICAL TURBOCHARGED ENGINETYPICAL TURBOCHARGED ENGINE

TROUBLESHOOTINGTROUBLESHOOTING

REQUIRE SKILL AND SHOULD NOT ASSUME REQUIRE SKILL AND SHOULD NOT ASSUME INSTANTLY FUEL INJECTION SYSTEM INSTANTLY FUEL INJECTION SYSTEM WHEN ENGINE RUNNING ROUGH.WHEN ENGINE RUNNING ROUGH.

OTHER SYSTEM MAY CAUSE ROUGH OTHER SYSTEM MAY CAUSE ROUGH RUNNING SUCH AS IGNITION SYSTEM OR RUNNING SUCH AS IGNITION SYSTEM OR INDUCTION SYSTEM.INDUCTION SYSTEM.

FOLLOW TROUBLESHOOTING CHART FOLLOW TROUBLESHOOTING CHART PROVIDED TO HELP YOU IN DETERMINE PROVIDED TO HELP YOU IN DETERMINE THE CAUSE OF ROUGH RUNNING.THE CAUSE OF ROUGH RUNNING.

OVERHAULOVERHAULFUEL INJECTION SYSTEM ARE NORMALLY FUEL INJECTION SYSTEM ARE NORMALLY OVERHAUL TOGETHER WITH AN ENGINE OVERHAUL TOGETHER WITH AN ENGINE OVERHAUL.OVERHAUL.

OVERHAULING ENTAILS SPECIALISED OVERHAULING ENTAILS SPECIALISED TOOLS, FLOW BENCHES AND SPECIALISED TOOLS, FLOW BENCHES AND SPECIALISED TRAINING.TRAINING.

UNLESS EMPLOYED BY OVERHAUL UNLESS EMPLOYED BY OVERHAUL STATION, YOU ARE ORDINARILY LIMITED STATION, YOU ARE ORDINARILY LIMITED TO BASIC INSPECTION AND FIELD TO BASIC INSPECTION AND FIELD ADJUSTMENT ONLY.ADJUSTMENT ONLY.

THe endTHe end

05 piston 2-3 fuel metering system

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