Stihl 09 010 011 Workshop Manual - The Bakelite Radio -...

STIHL 009, 010, 011 1

SERVICE MANUALSTIHL 009, 010, 011

FOREWORD

This Service Manual covers model 010chain saws up to machine number7 900 000 as well as later machinesunless technical information bulletinshave been issued in the meantimewith updated repair procedures.

Models 009 and 011 have substantiallythe same constructional features asmodel 010 chain saws. This ServiceManual can therefore be used for the009 and 011 chain saws as well.

In the event of faults it is quite possiblethat a single fault may have severalcauses. It is therefore advisable toconsult the "Troubleshooting Chart"in each chapter when tracing faults.We also recommend that you makeuse of the exploded views in theillustrated parts lists when carrying outrepair work.

This service manual and all technicalinformation bulletins are intendedexclusively for the use of STIHLservicing dealers and staff and must notbe passed on to third parties.

SPECIAL TOOL MANUAL

Repair work is made considerably Our special tool manual illustrateseasier if the chain saw is mounted on and lists the part numbers of ailassembly stand 5910 850 3100. The available machine-related tools assaw is easily secured to the stand by well as general purpose tools for allmeans of the bar mounting stud and machines.collar nut.

The special tool manual is availableWhile on the assembly stand the chain in several languages and can besaw can be swivelled into any required ordered by quoting the appropriateposition within a certain range to suit part number listed hereunder.the repair in question. This not onlyhas the advantage of keeping the German 0455 901 0023component in the most convenient English 0455 901 0123position for the repair but also leaves French 0455 901 0223both hands free for the work and thus Spanish 0455 901 0323effects a considerable time saving. Yugoslav 0455 901 0423

Swedish 0455 901 0523Italian 0455 901 0723Portuguese 0455 901 1223

STIHlAndreas StihlPostfach 1760D-7050 Waiblingen

STIHL 009, 010, 011 2

CONTENTS

1. Specifications 4 3.7 Installation of 4.5.2 Adjusting Breaker-Crankshaft Controlled Ignition 34

1.1 Engine 4 - Assembly of 4.6 Magneto Edge Gap1.2 Fuel System 4 Crankcase 16 on Breaker-1.3 Ignition System 5 3.8 Leakage Testing the Controlled Ignition 341.4 Tightening Torques 5 Crankcase 181.5 Cutting Attachment 6 3.8.1 Pressure Test 191.6 Weights 6 3.8.2 Vacuum Test 201.7 Special Accessories 6 3.8.3 Replacing the Oil 5. Rewind Starter 35

Seals 205.1 Construction and

Operation 352. Clutch, Chain Drive 5.2 Troubleshooting Chart 35

and Chain Brake 7 5.3 Disassembly 364. Ignition System 21 5.4 Replacing the

2.1 Construction and Operation 7 Starter Rope 362.1.1 Clutch and Chain 4.1 Construction 21 5.5 Replacing the

Sprocket 7 4.2 Description of Rewind Spring 372.1.2 Chain Brake 8 Operation 21 5.6 Tensioning the2.2 Troubleshooting Chart 8 4.2.1 Breaker-Controlled Rewind Spring 372.3 Repair 9 Magneto Ignition 22 5.7 General Maintenance 372.3.1 Disassembly 4.3 Troubleshooting

and Assembly of Clutch 9 Chart 232.3.2 Disassembly of 4.4 Function and Repair

Chain Brake 10 of Components 24 6. AV Handle System 382.3.2.1 Assembly of Chain Brake 10 4.4.1 Spark Plug 24

4.4.2 Ignition Lead 25 6.1 Construction and4.4.3 Ground Lead Contakt 26 Operation 384.4.4 Flywheel 27 6.2 Repair 38

3. Engine 11 4.4.5 Ignition Armature 284.4.5.1 Resistance Test on

3.1 Construction 11 Primary Winding 29 7. Chain Lubrication 393.2 Troubleshooting Chart 11 4.4.5.2 Resistance Test on3.3 Exposing the Cylinder 12 Secondary Winding 29 7.1 Construction and3.4 Disassembly of 4.4.5.3 Disassembly and Operation of

Cylinder and Piston 12 Assembly 29 Oil Pump 393.5 Assembly of Piston 4.4.6 Condenser 30 7.2 Troubleshooting Chart 40

and Cylinder 14 4.4.7 Contact Set 31 7.3 Oil Tank/Tank Vent 413.6 Disassembly of Crank- 4.5 Ignition Timing 32 7.4 Notes on Repair 41

case - Removal of 4.5.1 Checking Breaker- 7.5 Disassembly and RepairCrankshaft 15 Controlled Ignition 33 of Pump Housing 42

STIHL 009, 010, 011 3

8. Fuel System 43

8.1 Construction andOperation of Carburetor 43

8.1.1 Operation of Fuel Pump 438.1.2 Operation of Carburetor 438.2 Troubleshooting Chart 458.3 Leakage Test

(Pressure Test)on Carburetor 47

8.4 Disassembly ofCarburetor 47

8.5 Repair of Carburetor 488.6 Carburetor Adjustment 508.6.1 Notes for Fine Adjust-

ment of Carburetor 508.7 Fuel Line 518.8 Tank Vent 518.9 Air Filter and

Choke Valve 52

STIHL 009, 010, 011 4

1. SPECIFICATIONS

1.1 Engine Single cylinder two-stroke engine with specially processed cylinder boreDisplacement 009, 010: 37 cm³ (2.26 cu. in)Bore 009, 010: 36 mm (1.42 in)Displacement 011: 41 cm³ (2.50 cu. in)Bore 011: 38 mm (1.50 in)Stroke: 36 mm (1.42 in)Compression ratio: 9.8:1Max. torque: 1.8 Nm (1.3 Ibf. ft)

at 4500 r.p.m.Rated speed, off load withbar and chain: 9500 - 9800 r.p.m.Mean idle speed: 2200 - 2400 r.p.m.Crankshaft: Drop forgedCrankshaft bearings: 2 needle sleevesCrankpin: 13 mm (0.51 in) dia.Big-end bearing: Cylindrical rollers without cagePiston pin: 9 mm (0.35 in) dia.Small-end bearing: Needle sleeveRewind starter: Pawl engagement with automatic

starter rope rewind mechanismStarter rope: 3.5 mm (0.14 in) dia.,

960 mm (38 in) longClutch: Centrifugal clutch without

linings, 64 mm (2.5 in) dia.Clutch engages at: 3200 - 3300 r.p.m.Crankcase leakage testwith overpressure: 0.5 bar (7.1 Ibf/in²)with vacuum: 0.5 bar (7.1 Ibf/in²)

1.2 Fuel System Carburetor: All-position diaphragm carburetorwith integral fuel pump

Adjustment:High-speed adjustment screw H: Open 1 turnLow-speed adjustment screw L: Open 1 turn

(basic setting starting with screwslightly against their seats)

Carburetor leakage testwith overpressure: 0.4 bar (5.7 Ibf/in²)Fuel capacity: 0.26 L (0.55 US pt)

STIHL 009, 010, 011 5

Fuel mixture: Regular grade gasoline andbranded two-cycle engine oilMix ratio 1:40 with STIHLtwo-cycle engine oil: 1:25 withother branded two-cycleengine oils

Air filter: Large area felt mat

1.3 Ignition System Type: Breaker-controlled magnetoignition

Magneto edge gap: 5 mm (0.2 in)Ari gap: 0.2 mm (0.008 in)Ignition timing: 1.8-2.1 mm before T D.C.Ignition advance angle: 23°-24°Breaker point gap: 0.3-0.4 mm (0.012-0.016 in)Condenser: Capacitance 0.17 µFIgnition armature: Coil winding resistance

Primary Secondary0.8-1.3 Ω 7.2-8.8 kΩ

Spark plug (suppressed): Bosch WSR 6 F orChampion RCJ 6 YHeat range 200Electrode gap 0.5 mm (0.02 in)

Spark plug thread: M 14x1.25; 9.5 mm (0.37 in) long

1.4 Tightening Torques Crankshaft nut(ignition side) M 8x1: 30 Nm (22.1 Ibf. ft)Clutch (sprocket side): 30 Nm (22.1 Ibf. ft)M 6 socket head screws: 10 Nm (74 Ibf. ft)M 5 pan head screws: 5 Nm (3.7 Ibf. ft)M 4 pan head screws: 2.5 Nm (1.8 Ibf. ft)M 5 nuts: 5 Nm (3.7 lbf. ft)Spark plug: 25 Nm (18.4 Ibf. ft)

STIHL 009, 010, 011 6

1.5 Cutting Attachment Guide bars: STIHL Standard guide barswithout stellite-tipped noseSTIHL Duromatic guide barswith stellite-tipped noseSTIHL Rollomatic guide barswith sprocket noseAll types with corrosion-resistantfinish and induction hardened rails

Bar lengths: Duromatic 30 and 35 cm (12 and 14 in)Rollomatic 30, 35 and 40 cm(12, 14 and 16 in)

Chain: 9.32 mm (3/8")-Oilomatic-Picco

Chain sprocket: 6-tooth for 3/8" Picco pitchChain speed: 13 m/s (42.6 ft/sec) at 7000 r.p.m.Chain lubrication: Speed-controlled oil pump with

Diaphragm

Oil delivery rate: 6-12 cm3/min (0.37-0.74 cu. in/min)at 7000 r.p.m.

Oil tank capacity: 0.28 L (0.59 US pt)

1.6 Weights Model: 009 010 AV 011 AVDry powerhead with30 cm bar and chain: 4.3 kg 4.6 kg 4.7 kg

(9.51 b) (10.1lb) (10.4Ib)

1.7 Special Accessories STIHL repair kit 009, 010, 011 1120 900 5000Set of gaskets 009, 010, 011 1120 007 1050

STIHL 009, 010, 011 7

The construction of the clutch isidentical on both models of the saw(with and without chain brake).

While the engine is running at idlespeed there is no change in theshape of the clutch, i.e. its outsidediameter remains constant becausethe rigidity of the laminate block'ssmallest cross section is greaterthan the centrifugal force applied.As engine speed increases the outerdiameter of the clutch becomeslarger when the centrifugal forceovercomes the rigidity of thelaminate block. This causes theclutch to be pressed against theclutch drum and thus transmit enginetorque positively via the clutch drumand the chain sprocket to the sawchain.

The rigidity of the clutch is designedso that the clutch begins to makecontact with the clutch drum at anengine speed of approx. 3200 r.p.m.

The clutch engages fully above thisspeed. It is therefore very importantto set the carburetor to the correctidle speed in order to insure thatthe clutch engagement speed(3200 r.p.m.) is not reached whenthe engine is idling.

The transmission of power from theengine to the saw chain is effectedvia a centrifugal clutch which has nolinings.

The clutch consists of a laminate blockmade up of seven separate metalsheets which are riveted together. Thelaminate block is screwed to thecrankshaft. A cranked U-plate is fittedbetween the laminate block and theclutch drum and acts as a guard whichprevents parts of the clutch comingadrift in the event of breakage.

Clutch with cranked U-plate in position Component parts of clutch

2. CLUTCH,CHAIN DRIVE ANDCHAIN BRAKE

2.1 Constructionand Operation

2.1.1 Clutch andChain Sprocket

STIHL 009, 010, 011 8

2.1.2 Chain Brake

The chain brake is a spring-loaded The chain brake is disengaged by The chain brake is engaged byband brake without any friction linings. pulling the hand guard back toward moving the hand guard toward theIts main components are the brake the handlebar. This movement is bar nose. This movement unlatchesband, tension spring, hand guard and transmitted via a lever system which the locked brake lever and causesthe lever system. preloads the tension spring and re- the brake band to be clamped

leases the brake band. around the clutch drum by the forceThe chain brake is actuated via the of the preloaded tension spring. Thehand guard which can be used to The actuating lever, which is attached cluch drum and saw chain aredisengage or engage the brake. to the hand guard, remains locked in brought to a standstill in a split

the idle position after the operator second.releases the hand guard.

2.2 Troubleshooting Chart

Condition Cause Remedy

Saw chain turns at idle speed Engine idle speed too high Readjust at idle speedadjusting screw

Clutch broken Fit new clutch

Excessive chain sprocket wear Incorrect chain tension Tension chain correctly

Saw chain does not stop Tension spring broken Fit new tension springimmediately when chain brake isactuated

STIHL 009, 010, 011 9

2.3 Repair

2.3.1 Disassembly andAssembly of Clutch

First remove the chain sprocket cover Caution: The clutch has a lefthandand the cutting attachment. On Quick- thread - unscrew it clockwise!stop models it is necessary to dis-engage the chain brake so that the After unscrewing the clutch, remove thebrake band releases the clutch drum. chain sprocket, needle cage and thrust

washer from the crankshaft. ExamineTake out the spark plug and fit the clutch for signs of cracks or breaks.locking screw in its place. Use the If hairline cracks are found in thespecial wrench to turn the clutch and sprung part of the clutch, fit a newthe crankshaft clockwise until the clutch. The cranked U-plate shouldpiston head butts against the locking also be inspected for hairline cracks.screw. Now use wrench to unscrew If any are found, fit a new Crankedthe clutch. U-plate. Wash needle cage, thrust

washer and stub of crankshaft withclean gasoline. Replace needle cageif it is faulty.

Lubricate needle cage, thrust washerand stub of crankshaft withantifriction bearing grease beforeassembly. When refitting the clutchmake sure that the side on which thethread is counterbored to a depth ofabout 2 mm (0.08 in) faces thecrankcase. Tighten down clutchwith the wrench to a torque load of30 Nm (3.0 kpm).

Top: Top:Locking screw 1107 191 1200 Wrench 1113 890 3600

Bottom: Bottom:Locking screw in position Unscrewing the clutch Counterbored side of clutch

STIHL 009, 010, 011 10

2.3.2 Disassembly ofChain Brake

2.3.2.1 Disassembly ofChain Brake

Top:Detaching tension spring Top:

Brake band, brake lever and tension spring inCenter: positionRemoving retaining washer

Bottom:Bottom: Fitting tension spring with installing tool

Removing plastic cover Removing brake band 1117 890 0900

The chain brake components are inte-grated in the chain sprocket cover. Itis therefore necessary to remove thesprocket cover to gain access to thebrake components. After removingthe sprocket cover, engage the chainbrake, unscrew the plastic cover anddetach the tension spring from the pinin the housing. Remove retainingwasher from brake lever pivot pin andthen prise brake lever together withthe brake band and the tension springout of their seats in the cover. Therelay lever and actuating lever cannotbe disassembled. If either one ofthese levers is faulty the completechain sprocket cover (1120 640 1740)must be replaced.

Check levers and brake band forsigns of wear. Renew damaged partsand apply a little grease to the pivotpoints before reassembly.

First engage brake band in the brakelever. Then attach the tension springto the brake lever and install the pre-assembled parts in the chainsprocket cover.

Fit the retaining washer and use in-stalling tool to attach tension springto the retaining pin. Finish off bysecuring the plastic cover.

STIHL 009, 010, 011 11

3. ENGINE

3.1 Construction

Series 010 chain saws are powered The crankcase is a two-part pressure The connecting rod is supported byby an air-cooled, single cylinder two- die casting made of a magnesium cylindrical rollers, i. e. without astroke engine. alloy. The drop-forged crankshaft is bearing cage, on the crankpin and

supported in two needle sleeves. Two a needle sleeve on the piston pin.oil seals, one for each half of thecrankcase, hermetically seal the The cylinder and piston are made ofcrank chamber. an aluminium alloy. The cylinder bore

is coated in a special process.


Check fuel system, carburetor, air filter and ignition system before looking for faults in the engine.

Condition Cause Remedy

Engine does not start easily, Oil seals in crankcase leaking Replace oil sealsstalls at idle speed, but runsnormally at full throttle

Carburetor flange leaking, Fit new carburetor flangecracked

Crankcase damaged (cracks) Replace crankcase

Engine does not deliver full Secondary air seepage into Fit new carburetor flangepower or runs erratically engine because of faulty

carburetor flange

Piston ring leaking or broken Replace piston ring

Engine overheats Insufficient cylinder cooling. Thoroughly clean all coolingAir inlets in fan housing blocked air openingsor cylinder cooling fins clogged with dirt

STIHL 009, 010, 011 12

Unscrew the collar nut and take off the First drain the fuel and oil tanks and head screw from the front vibrationchain sprocket cover. Remove flat remove the spark plug. Unscrew the damper.head screw from rear vibration dam- four self-tapping screws from theper. Unscrew the fan housing and pull handle moulding, take off the mould- Unscrew the two cylinder baseoff the spark plug terminal. ing and disconnect throttle cable from screws - which secure the cylinder

throttle trigger. Push the handle to the crankcase - and then pull themoulding back into position to prevent cylinder off the piston.

Once the muffler is removed the the throttle trigger and flat springcooling fins of the cylinder are easily dropping out.accessible. They should be thorough-ly cleaned and examined for signs of Now take off the rear handle togetherdamage (cracks, broken cooling fins with the handlebar. To do this, un-etc.). screw the M 5 hexagon nut and flat

Top: Top: Top:Unscrewing the fan housing Removing the handle moulding Removing flat head screw

Bottom: Bottom: Bottom:Unscrew the muffler Removing hexagon nut from handlebar Removing cylinder basescrews

3.3 Exposing the Cylinder 3.4 Disassembly of Cylinderand Piston

STIHL 009, 010, 011 13

Top: Top:Top: Wooden assembly block 1108 893 4800 Removing wire retainerClamp 1120 893 9100

Bottom: Bottom:Bottom: Assembly block fitted between crankcase Pressing out piston pinClamp in position and piston with drift 1114 893 4700

Caution: The cylindrical rollers in the Before removing the piston it must be If the piston pin is stuck as a result ofbig end are not held in a bearing cage. decided whether or not the crankshaft carbonization, tap it out lightly with aThe special clamp must therefore be is to be removed as well, i. e. the hammer and the drift. It is essential topushed over the big end immediately wooden block which is used to lock counterhold the piston to insure thatafter taking off the cylinder in order to the crankshaft to facilitate removal of no jolts are transmitted to the con-prevent the cylindrical rollers drop- the flywheel and clutch must then be necting rod.ping into the crankcase if the connect- fitted between the crankcase and theing rod shifts sideways. piston.

To remove the piston, first take outthe two wire retainers which securethe piston pin and use the drift topress the piston pin out of the needlecage.

STIHL 009, 010, 011 14

3.5 Assembly of Piston andCylinder

Use a new muffler gasket whenrefitting the muffler.

Tightening cylinder base screws withArrow must point toward flywheel Fitting the cylinder torque wrench

Now insert the two wire retainers and Now reassemble the spark plug, ignimake sure they are properly seated. tion lead terminal, muffler, fan housThey must fit snugly in the grooves. ing, rear handle and handlebar,

throttle cable and handle mouldingand the chain sprocket cover.

As there are no longer any matching Fit new cylinder gasket on the crank-categories to observe the piston and case. Lubricate piston and piston ringcylinder can be replaced separately. with oil. The piston ring groove has noLubricate the needle cage in the small fixing pin; the piston ring can thereforeend with oil before installing the be fitted in any position.piston. Position piston on connectingrod so that stamped marking (arrow)points toward the flywheel. Use the clamping strap to compress

the piston ring around the piston andNow fit piston pin in piston and con- then push the cylinder over the piston.necting rod. To do this, push assembly The cylinder`s exhaust port must facedrift through piston bore and connec- toward the flywheel.ting rod (needle cage) to line the boresconcentrically. Push piston pin into thepiston. Move piston to and from to Align cylinder, insert cylinder baseease insertion of the piston pin. screws and preload them initially to

a torque of 6-7 Nm (0.6-0.7 kpm).The piston pin must move freely Then finally tighten to a torque ofin its bore. Never use force during 9.5-12 Nm (1.0-1.2 kpm).assembly.

STIHL 009, 010, 011 15

3.6 Disassembly of Crank-case - Removal ofCrankshaft

The ignition side of the crankcase stillcontains the ignition, a vibration dam-per, fuel line with pickup body as wellas a needle sleeve and the oil seal.

Use a screwdriver to knock the oilseals out of their seats from the in-side to the outside, but remove thecontact set first.

Top: Top:Removing key Driving out the crankshaft

Center and bottom: Bottom:Removing the hand guard Knocking back cylindrical pins Knocking out oil seal

To remove the crankshaft, first drainthe fuel and oil tanks. Then disas-semble the rear handle and handle-bar, fan housing, muffler (3.4), theclutch (2.3.1), flywheel (4.4.4), car-buretor (8.4) and hand guard. Re-move cylinder and gasket and fit thespecial clamp in position (3.4).

Remove key from crankshaft stub atignition side. Knock the twocylindrical pins back into the ignitionside of the crankcase and thenunscrew the seven flat head screwsat the sprocket side. The two halvesof the crankcase can now be split bytapping the sprocket end of thecrankshaft with a soft-nosedhammer. The crankshaft should nowslide out of the bearing when thumbpressure is applied.

The sprocket side of the crankcasestill contains the oil pump (7.4), thechain tensioner, a vibration damper,a needle sleeve and the oil seal.

STIHL 009, 010, 011 16

3.7 Installation of Crankshaft- Assembly of Crankcase

If the old crankcase is used again,carefully clean the sealing faces. Usea scraper or similar suitable tool toclean off gasket residue before fittingthe new gasket.

The crankshaft bearings (needlesleeves) should be pressed into thecrankcase halves from the inside tothe outside. Do not heat the crank-case for this purpose.

The needle sleeves will only be cor-rectly seated in the crankcase if thepress arbor is used.

Important: The needle sleeves mustbe positioned on the press arbor sothat the arbor's large diameter buttsagainst the reinforced rim of theneedle sleeve.

The needle sleeves are then placedin the crankcase and pressed homeuntil the arbor butts against the crank-case.

Then use press sleeve to press in theoil seals from the outside to the inside.

If the crankcase is damaged in anyway it must be replaced as a com-plete unit (both halves). Alwaysinstall new needle sleeves and oilseals in such a case. All other partswhich are still serviceable can thenbe transferred from the old to thenew crankcase.

Top:Cleaning sealing faces

Center:Needle sleeve correctly positioned

Driving out needle sleeve Bottom:with press arbor 1120 893 7200 Pressing in needle sleeve

Use the press arbor to drive theneedle sleeves out of the crankcase,from the outside to the inside in eachcase.

STIHL 009, 010, 011 17

Top: Top:Press sleeve 1120 893 2400 Cylindrical rollers held in position by grease

Bottom: Bottom:Pressing oil seal into position Clamp 1120 893 9100 in position Cutting away gasket web at cylinder opening

The oil seals should be perfectly flush If a new crankshaft is being fitted,with the crankcase faces. Lightly first fit 12 new cylindrical rollers ingrease the sealing lips of the oil seals the crankshaft groove by coating theand the needle sleeves after installa- groove with grease (0781 389 3138)tion. Use grease 0781 120 1109 for and then sticking the cylindricalthis purpose. rollers one by one to the grease.

Hold the crankshaft horizontally andcarefully fit the connecting rod over

If the oil seals are replaced without the cylindrical rollers.removing the crankshaft, use thepress sleeve to install them. Now fit the special clamp over the

connecting rod to prevent the con-necting rod slipping out of position

during assembly and the cylindricalrollers dropping out of the crankshaftgroove.

Coat the mating faces of the twocrankcase halves with sealing paste(0783 810 1101) and place thegasket on the clutch half of thecrankcase, but first cut away thegasket web across the cylinderopening.

Fit thrust washer in recess on clutchhalf of crankcase and insertcrankshaft, short stub first, into thecrankcase until is butts against thethrust washer. Fit the ignition half ofcrankcase over the other crankshaftstub (do not forget the thrustwasher), align the two crankcasehalves and then knock in the twocylindrical pins.

STIHL 009, 010, 011 18

3.8 Leakage Testing theCrankcase

Defective oil seals and gaskets or The crankcase can be checkedaccucracks in castings are the usual rately for leaks with the carburetor/causes of leaks. Such faults allow crankcase tester and the vacuumsupplementary air to enter the engine pump.and upset the fuel-air mixture.

This makes adjustment of theprescribed idle speed difficult or evenimpossible. Moreover, the transitionfrom idle speed to part or full throttleis not smooth.

Top:Carburetor and crankcase tester 1106 850 2900

Bottom:Removing gasket web at inlet port Vacuum pump 0000 850 3500

Then insert and tighten down theflat head screws to a torque of4 - 5 Nm (0.4 - 0.5 kpm).

Reassemble all remaining parts byreversing the disassemblysequence. Carry out crankcaseleakage test (3.8) and checkignition timing (4.5.2) before finalassembly.

Important: The web of thecrankcase gasket across the inletport must becut away beforefitting the diaphragm.

STIHL 009, 010, 011 19

Remove the carburetor and muffler Now fit test flange 1120 850 4210as well as the muffler gasket. together with two new gaskets (1120

129 0500 and 1120 129 0505) on thecrankcase.

Seal the cylinder exhaust port withthe sealing plate and test flange bymeans of two M 5x18 flat head Secure test flange 1118 850 4210 byscrews. means of two M 5x50 screws in place

of carburetor.

Also remove the diaphragm and thetwo gaskets.

3.8.1 Pressure Test

Top:Sealing plate 1120 855 8100 and Top:test flange 1120 855 4200 Test flange 1120 855 4215 in position

Bottom: Bottom:Exhaust port sealed Test flange 1118 850 4210 secured in position Sealing plate 1120 855 8105 installed

Unscrew the three pan head screwsfrom the oil pump, take complete oilpump out of crankcase anddisconnect hose. Use a screwdriverto prise off the circlip and thenremove the pump cover. Placesealing plate on flange face - to sealpulse hole - and screw oil pumpcover on top of it with the threeM 4x16 pan head screws.

Turn piston to top dead center(T D.C.) and check that spark plugis properly tightened down.

Connect tester's pressure hose tothe nipple of the test flange. Closebleed screw on rubber bulb andpump air into crankcase untilpressure gauge shows a reading of0.5 bar. If this pressure remainsconstant, the crankcase is airtight.However, if the pressure readingdrops the leak must be found and thefaulty part replaced.

STIHL 009, 010, 011 20

3.8.2 Vacuum Test 3.8.3 Replacing the Oil Seals

Leakage test with vacuum pump Puller 0000 890 4400 in position

Oils seals tend to fail when they are must be replaced even if no leaks The oil seals can be replaced with-subjected to a vacuum. During the were found in the previous pressure out disassembling the crankcase. Topiston's induction stroke the sealing test. do this, first remove the clutch (2.3.1),lip lifts off the crankshaft owing to the flywheel (4.4.4) and the contact setlack of internal counterpressure. (4.4.7).The primary lead can be left on

the contact set.An additional test can be performedwith the vacuum pump to detect this Both oil seals, on the ignition andfault. The preparations for this test are clutch sides, can be pulled out of theirthe same as described for the pres- seats with puller 0000 890 4400.sure test (3.8.1).

Screw the No. 5 jaws to the puller andConnect suction hose of vacuum push the jaws into the oil seal bypump to nipple of test flange. Then pressing them down lightly and turn-pull out pump handle until the pres- ing at the same time.sure gauge indicates a vacuum of0.5 bar. When you release the pump Open up the jaws by turning the winghandle the non-return valve automati- nuts and then screw down the spindlecally seals the suction hose. to pull the oil seal out of its seat.

If the vacuum reading remains con- Installation of the new oil seals isstant or drops no further than 0.3 bar, described under 3.7.the oil seals are in good condition.However, if the vacuum continues todrop (down to 0 bar), the oil seals

STIHL 009, 010, 011 21

4. IGNITION SYSTEM 4.2 Description of Operation

4.1 Construction

The 010 is equipped with a breaker- Every magneto ignition system ope- voltage is principally depended on thecontrolled magneto ignition system rates on the principle of magnetic strength of the primary current whichwhich requires neither a battery nor induction. On the breaker-controlled generates the magnetic field and thea generator. ignition system (and transistorized ratio of turns between the primary and

ignitions) this involves only "dynamic secondary coils (transformation ratio).induction".

The Phelon ignition system is of com-ponent-type construction (ignition ar- In dynamic induction the electricmature and control unit are arranged current is generated in a conductorseparately) and consists of three main by moving the conductor through theparts - the flywheel (magnet wheel), flux lines of a magnetic field. Theignition armature and the control unit. magnitude of the induced voltage is

basically dependent on the strengthThe flywheel carries the permanent of the magnetic field and the speed ofmagnet with a north and south pole the flux change. This in turn is in-and is located on the crankshaft stub. fluenced mainly by the intensity of theThe ignition armature is mounted in movement.the crankcase on the periphery of theflywheel and can be adjusted within In terms of the magneto ignitioncertain close limits by means of slots system this means: As the flywheelin the iron core. rotates the flux lines flowing between

the poles of the permanent magnet,The ignition's control unit, i. e. the con- from north pole to south pole, createtact set with condenser, is screwed to a magnetic flux in the iron core of thethe crankcase behind the flywheel. coils. The flux lines of this magnetic

field cut through the wire windings ofthe respective coil and induce a lowtension current. The magnitude of thevoltage is, therefore, basically dependent on the rotational speed of theflywheel.

In the case of static induction on theother hand, the voltage is created in aconductor by a magnetic field changing its strength or flow direction, theconductor being situated in the magnetic field which is produced by anelectric current (transformer principle). The magnitude of the induced

STIHL 009, 010, 011 22

4.2.1 Breaker-ControlledMagneto Ignition

Diagram of ignition system:4 Contact breaker

1 Flywheel 5 Condenser2 Permanent magnet with north and 6 Spark plug

south poles and pole shoes 7 Ignition stop switch3 Ignition armature with primary and 8 Air gap

secondary windings 9 Edge gap

When the magnet poles of theflywheel pass the iron core of thearmature coils a low-tension voltageis induced in the coils as a result ofthe magnetic flux.

Without any form of control the mag-netic flux would rise and fall like a

builds up a magnetic field (armaturefield) around the coil. This is opposedto the inducing magnetic field (exciterfield) and counteracts its tendency tochange the flux direction. The furtherthe flywheel rotates, the greater thetendency of the exciter field to changethe flux direction. The opposingarmature field and thus the primary

sine-wave and finally change direc-tion. The same applies for theelectric voltage. However, themagnitude of a voltage pulsegenerated in this way would not besufficient to produce a sparkover.

This means that the voltage curve

current must also increase accordingly.When the current finally reaches itsmaximum value the contact breakeropens the primary circuit - this instantis called "magnet breakdown". Thiscauses the magnetic field in thearmature core to suddenly changedirection and induce a high-tensionpulse in the armature's secondary

must be controlled. In this ignitionsystem the mechanical contact brea-ker performs the control function. Itis opened by the cam lobe groundon the hub of the flywheel andclosed by spring action. At themoment of maximum flux thecontact breaker, and also theprimary circuit, is closed. Theinduced voltage thus allows acurrent to flow in the primary windingwhich

winding which is proportional to thehigh number of turns in that winding.

This pulse is fed via the hightensionignition lead to the spark plug and isdischarged as a sparkover from thecenter to the ground electrode andthus ignites the fuel-air mixture.

A condenser is wired in parallel with thecontact breaker in the primary circuit inorder to prevent excessive sparking(arcing) between the breaker pointswhile they are opening and insure thereis no loss of energy or prematurecorrosion of the points.

The primary circuit is permanentlyclosed by means of the ignition stopswitch. This suppresses the abruptchange in direction of the magnetic fluxso that no further high-tension pulse canbe induced.

STIHL 009, 010, 011 23


Ignition system in order.Look for fault in fuel system and carburetor.

Replace condenser.Spark test positive?

Fit new flywheel.Is spark test positive?

Check ignition lead for break with ohmmeter.If break is detected, replace ignition lead.Does spark test now produce sparkover?

Does flywheel appear tobe in good condition?

Fit new spark plug.Is air gap correct?

Correct the air gap (0.3 mm).Is spark test positive?

Insert screwdriver in place of spark plug in spark plugterminal and hold about 4 mm (1/8“) away fromground. Sparkover?

Replace faulty ignition lead,repair contact spring or ignition stop switch.

Poor insulation on ignition lead?Is ignition stop switch touching contact spring?

Clean spark plug and reset electrode gap.Does spark test produce powerful spark?

Press terminal firmly onto sparkplug and fit spring if necessary.

Spark plug terminal firmly seated on spark plug?

Remove spark plug.Is it in good condition?

no

no

no

no

no

yes

no

no yes

no

no

no

no

yes

yes

Check armature and renew if necessary.Does engine now run after positive spark test?

Check condenser. In order?

Check connections at contact breaker andinspect breakers points. Renew burnt or pittedpoints. Check and correct ignition timing andmagneto edge gap. Does engine now run?

yes

yes

no

yes

no

no

STIHL 009, 010, 011 24

4.4 Function and Repairof Components

4.4.1 Spark Plug

The high-tension pulse generated inignition system is fed to the sparkplug and discharge as a sparkoverbetween the center and groundelectrodes.

When the spark plug is in goodcondition and the electrode gap iscorrect, the spark ignites the fuel-airmixture.

The appearance of the sparkplug'sinsulator nose gives valuableinformation with regard to the effectsof various operating conditions:

Troubleshooting on the ignitionsystem should always begin atthe spark plug.

In the event of starting difficulties,low engine power or misfiring etc.,unscrew the spark plug and checkwhether it is one of the typesapproved by STIHL.The ChampionRCJ 6Y suppressed spark plug is anapproved

alternative to the standard Bosch theWSR 6 F (formerly WKA 200 TR 6).These spark plugs cover a widethermal range and have betteroperating characteristics undersevere conditions.

Appearance of insulator nose Some conditions associatedwith appearance

Normal: grey/yellow to brown, dry Engine in order; spark plugheat range is correct

Sooted: velvelt-like, dull black coating Mixture too rich, lack of airof soot (dirty air filter, choke valve

partly closed), electrode gaptoo wide, heat range too high

Smeared with oil: coating of damp oil carbon Too much oil in fuel mixand soot

Overheated: welding beads on insulator Mixture too lean, spark plugnose, eroded electrodes loose, heat range too low

STIHL 009, 010, 011 25

4.4.2 Ignition Lead

Checking electrode gap Resetting electrode gap with Boschwith feeler gauge spark plug gauge Pulling out leg spring

Never use a steel wire brush for by pulling the rewind starter. The ignition lead feeds the high-cleaning a sooted or carbonized spark tension pulse generated in the arma-plug. Always use a brass wire brush If there is no sparkover although the ture to the spark plug. If its insulationfor this purpose and then blow out the spark plug is in good condition, first is brittle or damaged in any way aplug with compressed air. If the spark check the lead connections. Chafed sparkover to ground can occur andplug is smeared with oil, wash the insulation on the ignition or ground thus interrupt the ignition process.insulator nose with a grease solvent leads will cause a short-circuit toand blow out with compressed air. ground. If this is the case the engine The ignition lead must be renewed in

will either not start or only run errati- such a case.As the electrode gap becomes wider cally.as a result of normal erosion the gap To remove the ignition lead, dis-must be checked with a feeler gauge assemble the flywheel (4.4.4) andat regular intervals and reset as Before refitting the spark plug in the ignition armature (4.4.5.3). Unscrewnecessary. The specified gap is cylinder, clean the spark plug seat and the ignition lead from the wood screw0.5 mm and can be restored by make sure the sealing ring is in good on the high-tension output of thebending the ground electrode. How- condition. Tighten down the spark armature. Take off the rubber boot andever, always fit a new spark plug if the plug to a torque of 25 Nm (2.5 kpm). then pull out the ignition lead throughelectrodes are badly eroded. the cable clamp and crankcase. Use a

suitable pair of pliers to grip and pullAccurate checking of the spark plug the leg spring out of the ignition leadis possible only with a special spark terminal. Then pull ignition lead out ofplug tester. A provisional check can the terminal.be carried out by fitting the cleanspark plug in the ignition lead terminaland holding it against ground. Thereshould be a powerful sparkover at theelectrodes when the engine is cranked

STIHL 009, 010, 011 26

4.4.3 Ground Lead Contact

The ignition stop switch short circuitsthe ignition and thus stops theengine. The switch is installed in thefan housing and makes groundcontact when in the "STOP" position.

The ignition stop switch is simplylocated in the housing slot. To re-move it, push the spring strip out ofthe slot and pull the complete switchupward and out of the housing open-ing.

Top: Top:Ignition lead inserted through Spring strip of ignition stop switchterminal pushed out of slot

Bottom: Bottom:Screwing ignition lead onto armature Fitting leg spring Removing ignition stop switch

The new ignition lead must have alength of 370 mm.

Slip the rubber boot over one endof the lead and screw the leadfirmly onto the wood screw in thearmature - this is much easier if ahole is made in the center of thelead with a pointed tool.

Fit the armature and thread theother end of the ignition leadbetween the crankcase and cableclamp. Coat the free end of thelead with a little oil. Push theterminal over the end of the leadand use a suitable pair of pliers togrip and pull the lead out throughthe terminal. Pinch the hook of theleg spring into the center of thelead about 15 mm from the end ofthe lead. Pull lead back so that theleg spring locates in the terminal.Take out locking screw and refitspark plug. Push terminal ontospark plug and reassemble allother parts. Readjust air gap(4.4.5.3).

STIHL 009, 010, 011 27

4.4.4 Flywheel

the crankshaft stub an then back it offone full turn. Now hold the flywheeland tap the puller with a smallhammer. This releases the flywheelfrom its taper seat. Unscrew thepuller and take off the flywheel.

The contact spring is screwed to thecontact set. If the contact spring hasto be replaced, first remove the fly-wheel (4.4.4), then take out the 3 panhead screws and remove the contactset with contact spring and cableclamp from the crankshaft stub. Pushthe cable clamp to the rear andslacken off screw in contact set a fewturns. The contact spring can now bepushed to the rear and taken off.

Reverse the above procedure to in-stall the new contact spring. Resetbreaker point gap (4.4.7).

Top:Locking screw 1107191 1200 in position

Bottom:Releasing hexagon nutRemoving the contact spring

The flywheel has several functions. Itaccommodates the permanent mag-net for the ignition system with anorth and south pole (polarized in theengine's normal direction of rotation).The relatively large flywheel massinsures that the engine turns smooth-ly, i.e. it substantially suppresses thenormal irregularities of the engine'scombustion process.

The front of the flywheel is designedas a fanwheel to provide the neces-sary air for engine cooling

Six pawl detents are machined in thehub on the front side of the flywheelin order to transmit the startingtorque.

The flywheel is mounted at the igni-tion end of the crankshaft on a taperseat, located by means of a key andsecured with a hexagon nut.

To disassemble the flywheel, firstremove the fan housing, unscrew thespark plug and fit the locking screw inthe spark plug hole. Tighten it downby hand.

Turn flywheel counterclockwise untilthe piston head butts against thelocking screw. Use a ring or socketwrench to slacken off and remove thehexagon nut counter-clockwise.Screw flywheel puller as far as it willgo onto

STIHL 009, 010, 011 28

4.4.5 Ignition Armature

Top:Releasing flywheel with puller1116 893 0800

Bottom: 1 = Primary connectionTightening hexagon nut with 2 = Secondary connectiontorque wrench Key correctly positioned 3 = Ground connection

Before re-installing the flywheel, absorbed entirely by the taper seat. Itclean the crankshaft stub and the fly- is therefore absolutely essential towheel hub bore with a suitable de- insure that the crankshaft nut isgreasing agent (e.g. trichlorethlene, tightened down to the specified torquediluted nitro). Make sure the key is load of 25 Nm.correctly positioned.

Finish off by removing the lockingFit flywheel on the crankshaft so that screw, refitting the spark plug and thethe key locates in the slot in the fly- fan housing.wheel hub. The key is provided onlyto insure that the flywheel is correctlypositioned. The driving force betweenthe crankshaft and flywheel must be

On the ignition armature the primaryand secondary coils are arranged onthe center arm of the iron core andencased in a plastic compound tomake them moisture-proof. Threeelectrical connections emerge fromthe coil body, i.e. the primary andsecondary connections and theground connection.

There are two ways of testing theignition armature:

The resistance of both coil windingscan be checked with the aid of ohm-meter 5910 850 4800.

Accurate testing is performed with anignition coil tester.

STIHL 009, 010, 011 29

First remove the flywheel (4.4.4) andtake out the two contact set mountingscrews. Unscrew the cable clampfastening screw and then the two panhead screws on the ignition armature.Remove the ignition armature andcontact set. Unscrew the ignition leadfrom the armature and the primarylead from the contact set.

4.4.5.1 Resistance Test 4.4.5.2 Resistance Test 4.4.5.3 Disassemblyon Primary Winding on Secondary Winding and Assembly

Top:Removing the contact set

Bottom:Resistance test on primary winding Resistance test on secondary winding Unscrewing the ignition armature

To test the primary winding, first re- To test the secondary winding, holdmove the flywheel (4.4.4) and the banana-pin of one test lead againstcontact set. the leg spring in the spark plug ter-

minal and connect other test lead toThen disconnect lead from contact ground of ignition armature. A readingset. Clip one of the two test leads to of 7.2 to 8.8 (kΩ) should now be ob-the primary connection and the other tained in measuring range "Ωx1000"to ground of ignition armature. A (kΩ).reading of approx. 0.8 to 1.3 (Ω)should now be obtained in measuring If a different value is obtained,range "Ωx1". remove the ignition lead and carry out

the measurement again, holding oneIf the reading obtained deviates from test lead directly against the secon-this value the ignition armature must dary output of the ignition armature. Ifbe replaced. the deviation from the specified value

persists, the ignition armature mustbe replaced.

STIHL 009, 010, 011 30

4.4.6 Condenser

The condenser is wired in parallel withthe contact breaker. While the breakerpoints are opening the primary currentis fed briefly to the condenser until it ischarged. This insures that thestrength of the current flowing via thecontact breaker at this point is onlyminimal and thus suppressesexcessive sparking (arcing).

A faulty condenser is often the causeof premature erosion of the contactbreaker points and loss of ignitionvoltage. The condenser's storagecapacity is 0.17 µF and can bechecked with the ohmmeter or theBosch ignition coil and condensertester EFAW 106 A. To do this,remove the fan housing, flywheel,contact set and the condenser lead.

To check with the ohmmeter, connectone of the two leads to ground (e.g.cylinder fin) and hold the other on thecondenser connection. If thecondenser is in good condition, it willbe charged and the ohmmeter'spointer

Top:Setting gauge 1111 890 6400

Center:Securing the armature

Bottom: Checking condenser with ohmmeterPushing armature away from flywheel Checking air gap with feeler gauge 5910 850 4800

To reassemble, connect up primaryand ignition leads. Position ignitionlead on crankcase, fit the contact setand flywheel. Push ignition armatureaway from flywheel and secure inposition with pan head screws. Do notforget the ground lead.

Now align flywheel so that the area inwhich the magnets are embeddedcovers half of each of the two outerarmature arms. Insert setting gaugeor 0.2 mm gauge sheet betweenmagnet poles and armature arms,slacken off pan head screws andpress armature firmly against theflywheel. Then retighten the pan headscrews.

Take away the gauge and check theair gap with a feeler gauge. It shouldbe between 0.2 and 0.3 mm.

STIHL 009, 010, 011 31

4.4.7 Contact Set

the primary lead firmly into thehousing slot. The primary lead mustnot touch the flywheel. Furthermore,the cylindrical pin on the underside ofthe contact plate must be properlyseated in the locating hole provided inthe crankcase.

The contact breaker set consists of afixed contact, which is connected toground, and a moving contact breakerlever which is insulated from groundand connected to the ignition coil'sprimary connection and thecondenser. The contact set functionsas a switch which closes the primarycircuit and opens it again at the pointof ignition.

The service life of the heel on thecontact breaker lever is greatlydependent on proper lubrication. It istherefore important to insure that thegrease impregnated lubricating felt inthe contact plate is always in goodcondition.

The contact breaker points graduallywear as a result of erosion. Erodedcontacts widen the breaker point gapand cause ignition timing to beadvanced and the magneto edge gapto be reduced.

Partly eroded contact breaker pointscan be reset but badly burnt pointsnecessitate immediate replacement ofthe complete contact set. To do this,remove fan housing and flywheel,unscrew the two contact set mountingscrews and one screw on the cableclamp and then take out the contactset. Push cable clamp out of the way,take out fastening screw and removecontact spring and primary lead.

When installing the new contact setmake sure the cable clamp presses

Top:Removing contact set and cable clamp

Bottom:Removing mounting screw

should briefly move to about 0.2 (µF)in measuring range "µFx1" (/-µF =microfarad). If this is not the case thecondenser is faulty and a new onemust be installed. Always dischargethe condenser after each test byshorting it out (connecting lead toground).

If the Bosch tester EFAW 106 A isused for the test, follow theinstructions supplied with the unit.

If the condenser is faulty, thecomplete contact set must bereplaced (4.4.5.3).

Finish off by refitting the contact set,flywheel and fan housing.

Discharging the condenser

STIHL 009, 010, 011 32

4.5 Ignition Timing

The ignition timing on the breaker-controlled magneto ignition systemmust be set to 2.0 mm before T D.C.(top dead center). This means thatthe moving contact should just beginto lift off the fixed contact when thecrankshaft is in this position. Thecontact breaker points are fully openwhen the crankshaft is in the T.D.C.position; the breaker point gap mustbe 0.4 mm.

To adjust the breaker pointer gap,turn the crankshaft in the engine'snormal direction of rotation(counterclockwise) until the piston isat T D.C. The flywheel cam opens thecontact breaker lever fully in thisposition. Now slacken off the contactset and turn it until a breaker pointgap of 0.4 mm is obtained with aclean feeler gauge. Then retighten themounting screws. Check ignitiontiming and magneto edge gap.

The breaker point gap, ignition timingand magneto edge gap areinterrelated and none of these valuescan be altered without affecting theothers. However, this also means thatif one of these values is correct theother two should normally be correctas well. The dominating factor is themagneto edge gap. If variations areexperienced in practice, preferenceshould be given to maintaining thecorrect edge gap.

Finish off by checking the lubricatingfelt. It should be in good condition andsoaked with oil.

Top:Cylindrical pin on contact set

Bottom:Locating hole in crankcase Checking breaker point gap

STIHL 009, 010, 011 33

4.5.1 Checking BreakerControlled Ignition

To check ignition timing, remove thefan housing and spark plug. Screwthe holder into the spark plug holeand then insert the dial gauge, withtracer pin extension, in the holder.

Turn the flywheel to bring the pistonto T D.C. and then set the dial gaugepointer to "0" in this position. Attachterminal clips of ignition timing unitsecurely to cylinder fin and contactspring. Now turn flywheel backwardabout a quarter of a revolution.Switch

Top:Dial gauge with holder 1110 890 8600 and Top:tracer pin 1107 894 3000 Dial gauge set to "O"

Bottom: Bottom:Holder in position Ignition timing unit ready for test Timing marks on flywheel and crankcase

on ignition timing unit and turn fly-wheel slowly in the engine's normaldirection of rotation until the indicatorlamp on the timing unit lights up, orthe buzzer sounds.

The contact breaker opens in thisposition. The dial gauge should nowshow a reading of 2.0 mm. If this isnot the case, the ignition must beretimed.

On machines with a timing mark onthe flywheel, ignition timing ischecked by bringing the flywheel andcrankcase timing marks into align-ment. The indicator lamp on thetiming unit should just begin to glowin this position.

STIHL 009, 010, 011 34

4.5.2 Adjusting Breaker- 4.6 Magneto Edge Gap onControlled Ignition Breaker-Controlled Ignition

Resetting breaker point gap

lated. None of these values can bealtered without affecting the others.However, this also means that if oneof these values is correctly set theother two will normally be correct aswell. The dominating factor is themagneto edge gap. If any variationsare experienced in practice,preference should be given tomaintaining the correct edge gap.

Finish off by removing the testequipment and reassembling the saw.

The position of the magnet at thepoint of current interruption, i.e.ignition, is called magnet breakdownand is referred to in terms of themagneto edge gap. The magnetoedge gap is, therefore, the distancebetween the trailing edge of the northpole shoe and the left-hand edge ofthe center armature arm when thecontact breaker points begin to open.This distance is 5 mm.

The magneto edge gap has adecisive influence on the performanceof the ignition system. If it is too large,the ignition voltage during starting willbe too low; however, if it is too small,the engine will misfire at high speed.

If the ignition is properly timed themagneto edge gap will automaticallybe correct as the two factors areinterrelated. However, variations mayoccur as a result of an accumulationof maximum manufacturingtolerances. The edge gap should,therefore, also be checked wheneverthe ignition timing is adjusted.Preference should always be given tomaintaining the correct edge gapeven if this means that there areminor discrepancies in ignition timingand the breaker point gap.

To check the edge gap, first followprocedure for checking ignition timing.The magneto edge gap should thenbe measured at the moment thetiming unit's indicator lamp lights up(ignition point).

In addition to the preparationsdescribed under 4.5.1 (inserting thedial gauge) it is necessary to removethe flywheel in order to adjust ignitiontiming.

Turn clutch in engine's normaldirection of rotation (clockwise) untilthe dial gauge pointer remainsstationary (T D.C. position). Now setdial gauge pointer to zero. Turn clutchabout a quarter of a revolutionclockwise and then backward againuntil the dial gauge shows a readingof 2.0 mm. Switch on the ignitiontiming unit, slacken the contact setand turn it until the indicator lamp onthe timing unit just lights up.

Then retighten the contact setmounting screws and recheck ignitiontiming. If it is now between 1.9 and 2.1mm before T D.C., the breaker pointgap will be between 0.3 and 0.4 mm.

The breaker point gap, ignition timingand magneto edge gap are interre-

STIHL 009, 010, 011 35

The rewind starter mechanism ismounted on the starter post in thefan housing, directly in front of theflywheel. Its main components arethe starter rope with grip, rope rotorwith rewind spring and pawl. A springclip holds these components inposition on the post. The starterrope, which is wound onto the roperotor by the pre-

loaded rewind spring, rotates therotor when the starter grip is pulled.This causes the pawl to be movedoutward by the spring clip andengage the flywheelhub.

The torque produced by the starterrope is thus transmitted positively viathe flywheel and turns the crankshaft.

The withdrawn starter rope is auto-matically rewound onto the rope rotorby the preloaded rewind spring.

The rewind starter mechanism ispractically maintenance-free. Onlythe rope rotor post needs to be lubri-cated with non-resinous oil at regularintervals.

Remedy

Replace starter rope

Replace rewind spring

Thoroughly clean rewind starter

Apply a little paraffin to the rewindspring, then pull starter ropecarefully several times untilnormal action is restored

Cause

Rope pulled out too vigorouslyas far as stop or notpulled vertically

Spring overtensioned - noreserve when starter rope isfully extended

Rewind starter mechanism verydirty (dusty conditions)

The lubricating oil on the rewindspring becomes viscous at verylow outside temperatures(spring windings stick together)


Fault

Starter rope broken

Rewind spring broken

Starter rope difficult to pull andrewinds very slowly

5. REWIND STARTER


STIHL 009, 010, 011 36

5.3 Disassembly 5.4 Replacing theStarter Rope

Top: Top:Starter rope secured in rope rotor Pawl in position

Bottom: Bottom:Unscrewing the fan housing Special knots Fitting the spring clip

First unscrew the fan housingtogether with the rewind starter. Thenrelease tension on rewind spring. Todo this, pull starter rope partly out ofthe housing, hold the rope rotor firmlyand takeoff two or three turns of thestarter rope. Let go of rope rotor- itwill turn back and the rewind spring isthen relieved of preload.

There will, of course, be no preloadon the rewind spring if the starter ropeis broken. Now remove the deflectorand use a screwdriver or pliers toprise the spring clip off the starterpost. Then take the washer, roperotor and pawl off the starter post. Remove rope residue from rope rotor,

thread a new 3.5 mm dia. and 960mm long starter rope through the roperotor are secure it with an overhandknot. Push the other end of the ropethrough the hole in the fan housingand through the underside of thestarter grip and secure it with aspecial knot.

Lubricate the starter post withnonresinous oil. Slip rotor onto starterpost and turn it to and fro to engage

loop of rewind spring in recess ofannular rib. Now fit washer on starterpost and pawl in the rotor. Use ascrewdriver or suitable pair of pliers tofit spring clip on the starter post,making sure that its loop facesclockwise and engages on the pawl'sguide pin. Finish off by tensioning therewind spring (5.6).

STIHL 009, 010, 011 37

5.5 Replacing the 5.6 Tensioning the 5.7 General MaintenanceRewind Spring Rewind Spring

Rewind spring in position Tensioning the rewind spring

First remove the rope rotor and takeout any spring particles which arestill in the fan housing. The replace-ment spring is supplied ready forassembly and is held together by awire strap. It should be lubricated witha few drops of non-resinous oil beforeinstallation.

Position the rewind spring in the roperotor so that the outer spring loopengages on the lug in the fan housing.The wire strap is pushed off the springduring this operation.

If the spring comes out and uncoilsduring installation, refit it in the fanhousing in the clockwise direction,starting with the outer end and workinginward. Then refit the rope rotor.

Wind the starter rope clockwise ontothe rope rotor until the starter grip isabout 20 cm (8") away from the fanhousing. Grip rope next to rotor anduse it to rotate rotor two full turnsclockwise. This tensions the rewindspring. Now hold rope rotor firmly inposition, straighten out twisted ropeand pull it out of fan housing. Let goof rope rotor and slowly release ropeso that it winds onto the rotor.

The rewind spring is correctly ten-sioned when the starter grip sitsfirmly in the fan housing withouthanging to one side. If this is not thecase, tension rewind spring a furtherturn. When the rope is fully extendedit must still be possible to rotate therope rotor at least another half turnbefore maximum spring tension isreached. If this is not so, take off oneturn of the rope.

If the starter rope action becomesvery stiff and it rewinds very slowly ornot completely, it can be assumedthat the rewind starter is mechanicallyin order but plugged with dirt.

At very low temperatures the oil onthe rewind spring may thicken andcause the spring windings to stick to-gether. This has a detrimental effecton the operation of the rewind starter.In such a case it is sufficient to applya little paraffin to the rewind spring.

Then pull out starter rope carefullyseveral times until its normal smoothaction is restored. If clogged with dirtor resin, the entire rewind startermechanism, including rewind spring,must be removed from the machine.Take special care when removing thespring! Wash all parts in paraffin orclean gasoline.

Lubricate the rewind spring andstarter post with oil whenreassembling the mechanism.

STIHL 009, 010, 011 38

On filter cover

Unscrew flat head screw fromannular buffer (virbration damper).Remove filter cover and plate andthen unscrew hexagon nut and takeout annular buffer.

Note on repairs: If only one annularbuffer is faulty, always replace allthree annular buffers for safety rea-sons.

On handlebar

Unscrew the hexagon nut. Pullhandlebar off the collar stud and un-screw the annular buffer (vibrationdamper) and bracket from the sawhousing.

Do not forget the bracket (anti-shearelement) when installing the newvibration damper.

On rear handle

Unscrew M 5x18 flat head screw fromannular buffer (vibration damper).Swing handle upward and unscrewthe annular buffer and bracket fromthe saw housing.

Do not forget the bracket (anti-shearelement) when installing the newvibration damper.

The anti-vibration handle system re-duces engine and cutting attachmentvibrations to a minimum before theyreach the operator. This vibration in-sulation is achieved by means of re-silient anti-vibration mounts betweenthe chain saw housing and the frontand rear handles.

To insure that the full benefit of theAV handle system is maintained it isessential that the saw be operatedonly with completely intact vibrationdampers. Moreover, it is extremelyimportant to insure that the brackets(anti-shear elements) are always fit-ted at the front left on the handlebarand on the rear handle. The risk ofaccidents will be increased if the anti-shear elements are forgotten duringa repair.

6. AV HANDLE SYSTEM 6.2 Repair


Top: Removing flat headscrew

Bottom:Position of vibration dampers Unscrewing vibration damper with bracket Unscrewing the hexagon nut

STIHL 009, 010, 011 39

7. CHAIN LUBRICATION7.1 Construction and

Operation of Oil Pump

Schematic of oil pump

Top: 1 = FilterIntake stroke 2 = Feed bore

3 = Plunger with diaphragmBottom: 4 = Pulse chamberDelivery stroke 5 = Compression spring

and plunger fills with chain oil. The oilmust pass through a filter before itenters the pressure chamber.

The pressure in the pulse chamber ischanged by the downward stroke ofthe piston. This causes thediaphragm to be moved in theopposite direction and the plungerforces the chain oil out of thepressure chamber into a rubber hoseand from there to the cuttingattachment. A compression springbetween the diaphragm and thepump cover assists the action of thepressure against the diaphragm.

The oil delivery rate rises in analmost linear ratio to engine speedand, therefore, the chain speed. Thismeans there is always a sufficientsupply of lubricating oil to matchchain speed.

pump's pulse chamber is connectedto the crank chamber by a bore.

The upward stroke of the piston crea-tes a depression in the crankcasewhich is transferred via the housingbore to the pulse chamber. Thiscauses the diaphragm to move back.The plunger is attached to the dia-phragm and opens the oil feed bore.The ball check valve closes the oildelivery bore at the same time andthe space between the check valve

The oil pump is located on the clutchside of the crankcase. It supplieslubricating oil to the guide bar andchain while the engine is running.

The pump consists of the pumphousing, end cover, the diaphragmwith plunger, compression spring,check valve and oil filter.

The oil pump is not driven mechani-cally. It is operated by the alternatingpressure in the crankcase. The oil

STIHL 009, 010, 011 40


In the event of difficulties with thechain oil supply, always investigateand rectify the other possible sourcesof faults before disassembling the oilpump.

Remedy

Fill up with oil

Clean oil inlet hole

Wash out plunger guide boreand filter in clean gasolineand blow out with compressedair; replace if necessary

Wait approx. 5minutes until filter issaturated

Fit new crankcase

Replace seals

Replace diaphragm with plunger

Replace pump housing togetherwith diaphragm and plunger

Cause

Oil tank empty

Oil inlet hole in guide baris blocked

Plunger guide bore or filterblocked or delivery hosecracked

New filter installed

Cracks in crankcase

Seals on pump housing faulty

Diaphragm faulty

Plunger guide in pump housingworn or dirty

Fault

No oil supply to chain

Machine loses chain oil

Oil pump delivers too little oil

STIHL 009, 010, 011 41

7.3 Oil Tank/Tank Vent 7.4 Notes on Repair

Chain oil supply system Split pin in vent hole

sure in the oil tank. This is necessarybecause the pump would nototherwise operate, i. e. the airtightseal provided by the oil filler capwould cause a vacuum to be createdin the oil tank as the oil level dropsand thus negate the suction of the oilpump.

There is a vent hole in the crankcasebelow the chain oil outlet to insurethat equal pressures are maintainedinside and outside the oil tank. A splitpin is fitted in the vent hole whichallows air to enter but also preventsthe ingress of dirt and the loss ofchain oil from the tank. If the vent hole is caked with dirt, it

can blown be out with compressedair. Stubborn particles of dirt can beloosened by turning the split pincarefully to and fro and then blownout with compressed air.

If the two halves of the crankcase areseparated during a repair, the pulsehole in the sprocket side of thecrankcase should be examined fordeposits of foreign matter. If any arefound, they should be cleaned awaywith the pump housing removed.

If the machine has not been in use foran extended period, the pump plungermay be stuck in the pump housingowing to resin in the oil. In such acase the pump must be disassembledand washed in clean gasoline.

The chain oil tank is an integral part ofthe crankcase. The oil pump - whichis operated by the alternatingpressures in the crankcase - drawschain oil through a filter and into thepump housing. It then feeds it througha rubber hose to the oil inlet hole inthe guide bar.

A precondition for correct operation ofthe oil pump is that the pressure inthe pump housing during the intakestroke must be lower than the pres

STIHL 009, 010, 011 427.5 Disassembly and Repair

of Pump Housing

The filter can also be washed inclean gasoline. However, if it issaturated with resin it is best to fit anew filter.

The filter can be removed after takingoff the plastic washer which sits inthe groove of the hose nipple. Theplastic washer is used to locate thefilter element and must not beforgotten during reassembly.

Important: After installing a newfilter wait at least 5 minutes betweenfilling up with chain oil and starting.This period allows the filter to fill withchain oil, i.e. the lubrication system isthen primed and the saw is ready foroperation.

To remove the pump housing, firstunscrew the three pan head screws.Pull the pump housing out of thechain oil tank and disconnect thedelivery hose.

Prise the retaining ring off the pumphousing cover in order to disassem-ble the pump. The retaining ring isonly fitted for shipment and need notbe refitted when the pump isassembled.

Clean the pump housing by blowingout the oil hole with compressed air.Resinous deposits can be cleanedaway with gasoline. Always replacethe diaphragm if it is faulty. When re-assembling the pump make sure thatthe compression spring is fitted bet-ween the diaphragm and pumpcover, and not between thediaphragm and the housing as thiswould cause the pump tomalfunction.

Removing plastic washer

Top:Removing retaining ring

Bottom:Assembly sequence-diaphragm, compressionspring and pump cover

Top:Removing the oil pump

Bottom:Disconnecting delivery hose

STIHL 009, 010, 011 43

8. FUEL SYSTEM

8.1 Construction andOperation of Carburetor

The all-position diaphragmcarburetor consists of the fuel pumpand the carburetor body. The fuelpump operates as a completelyseparate and independent unitalthough it shares a commonhousing with the carburetor.

8.1.1 Operation of Fuel Pump

The pressure in the crankcase varieswith each stroke of the piston. Thepiston creates a depression in thecrankcase on its upward stroke andoverpressure on its downward stroke.This is utilized for actuation of thefuel pump. The chamber in front ofthe pump diaphragm (pulsechamber) is connected to the crankchamber by a pulse line. Thechanges in pressure act directly onthe pump diaphragm and cause it tomove in time with the piston. Controlis effected by means of two flapvalves stamped in the pumpdiaphragm.

The depression created by the up-ward stroke of the piston draws thepump diaphragm into the diaphragmchamber. This enlarges the pumpchamber and produces a vacuum.The inlet valve then opens and thehigher atmospheric pressure forcesfuel from the tank into the pumpchamber and presses the outlet valveagainst its seat.

The downward stroke of the pistonchanges the relative pressures. Anoverpressure is built up in the crankand pump chambers which presses

the diaphragm against the pumpchamber and exerts pressure on thefuel. The overpressure forces theinlet valve to close, while the outletvalve opens and allows fuel to flow tothe carburetor's needle valve.

8.1.2 Operation of Carburetor

The opening and closing action ofthe needle valve and, therefore, thesupply of fuel to the carburetor iscontrolled by the meteringdiaphragm. The metering diaphragmis in a position of rest whenatmospheric and diaphragm chamberpressures are equal (the chamberabove the diaphragm is connected toatmosphere).

The cone of the inlet needle is heldagainst its seat by spring pressure.

The metering diaphragm chamber isfilled with fuel when the engine isrunning. A depression is created inthe choke tube (venturi) during theinduction stroke. Fuel is drawn intothe choke tube through the jet boresbetween the choke tube and dia-phragm chamber. This is turn pro-duces a depression in the diaphragmchamber and atmospheric pressurepresses the metering diaphragm to-ward the carburetor body. The forcegenerated by the pressure differencex diaphragm area acts on the inletcontrol lever via the perforated discon the diaphragm, overcomes thespring force and lifts the inlet needleoff its seat. This allows fresh fuel to

flow from the pump chamber into thediaphragm chamber. The needlevalve closes again as soon as atmo-spheric pressure is reached in themetering chamber. Under normaloperating conditions the needle valvedoes not open and close constantly.The metering diaphragm actuallysettles down to a mean level, depen-ding on engine speed, and theneedle valve remains open relative tothe diaphragm's position.

The quantity of fuel drawn into thechoke tube depends on the amountof depression, and this in turn is in-fluenced by the position of the chokeand throttle valves. The volume offuel can be altered to suit differentoperating conditions by means of theadjustment screws in the idle andmain jets.

STIHL 009, 010, 011 44

4. Opening the throttle valve furtherbrings the main jet (valve jet), loca-ted at the narrowest point of thechoke tube, into operation andprovides the fuel required forfull-throttle operation.

the inlet when there is insufficientdepression in the choke tube.

3. During the changeover from idleto part or full-throttle sufficient fuelmust be drawn in with the suddenlyincreased flow of air when the throttleis opened. This is effected by meansof the secondary idle jet which isexposed to the effects of vacuum atthis point, thus producing the richer,igniteable mixture required.

Top: Top:Starting position Changing from idle to part or full-throttle

positionBottom:Idle position Bottom:

Full-throttle position1 - Pulse nipple2 - Inlet valve open 9 - Throttle valve3 - Fuel intake 10 - Secondary idle jet4 - Choke valve 11 - Primary idle jet5 - Valve jet 12 - Low-speed adjustment screw6 - High-speed adjustment screw 13 - Metering chamber diaphragm7 - Pump diaphragm (intake position) 14 - Metering diaphragm8 - Outlet valve closed 15 - Connection to atmosphere

16 - Inlet control lever17 - Inlet needle

(both adjustment screws are drawn offset by 90°; choke valve is shown integrated incarburetor only for this description)

Four basic operating conditions aredescribed below to explain the func-tion of the carburetor:

1. The choke valve is closed and thethrottle valve partly open during thestarting process. A powerfull va-cuum is created in the choke tubeduring the induction stroke becausethe entry of outside air is almost com-pletely restricted by the closed chokevalve. This means that the enginedraws in a large amount of fuelthrough all the jets and relatively littleair. A rich starting mixture is obtainedin this way. The choke valve must beopened as soon as the engine fires -the mixture would otherwise be toorich and stall the engine.

2. Very little fuel is required foridling. The choke valve is fully openand the throttle valve almostcompletely closed. The vacuum onlyacts on the primary idle jet so thatfuel is only drawn off through this jet.Owing to the pressure differencebetween the choke tube (venturi) andthe intake pipe behind the throttlevalve, air flows through thesecondary idle jet and the aircorrection jet into the idle chamberand prevents the mixture becomingtoo rich. However, because of thispressure difference it is necessary toprevent supplementary air gettinginto the diaphragm chamber, makingthe mixture too lean and causing theengine to stall. This problem iseliminated by a small plate in thevalve jet which closes against

STIHL 009, 010, 011 45


Fault

Carburetor floods –engine stalls

Engine does not respond properlyto throttle

Engine will not idle

Cause

Inlet valve not sealing.Foreign matter in valve seator cone damaged

Helical spring not located ondimple of inlet control lever

Perforated disc on diaphragmis deformed and pressesconstantly against inlet controllever

Inlet control lever too high(relative to design position)

Idle jet "too lean"

Inlet control lever too low (relativeto design position)

Vent bore to atmosphere blocked

Diaphragm gasket leaking

Metering diaphragm damaged

Throttle valve opened too farby idle speed adjustment screw

Remedy

Remove and clean orreplace inlet needle

Remove inlet control lever andrefit correctly

Fit new metering diaphragm

Set inlet control lever flush withtop edge of plate

Back off low-speed adjustmentscrew slightly (see CarburetorAdjustment)

Set inlet control lever flush withtop edge of plate

Clean bore

Fit new diaphragm gasket

Fit new metering diaphragm

Reset idle speed adjustmentscrew

STIHL 009, 010, 011 46

Remedy

Clean jet bores and blowout with compressed air

Turn low-speed adjustment screwslightly clockwise (see CarburetorAdjustment)

Set idle speed screw correctly

Clean air filter

Clean tank vent or replace ifnecessary

Seal connections and replacefuel line if necessary

Fit new pump diaphragm

Clean bores and ports

Clean fuel strainer

Cause

Idle jet bores or ports clogged

Idle jet too "rich"

Idle speed screw incorrectly set –throttle valve completely closed

Air filter plugged

Tank vent faulty

Leak in fuel line between tank andfuel pump

Pump diaphragm damaged

Main jet bores or ports blocked

Fuel strainer dirty

Fault

Engine stalls at idle speed

Engine speed drops quickly underload - low power

See also 3.2

STIHL 009, 010, 011 47

8.3 Leakage Test (Pressure Test)on Carburetor

First remove the filter cover and filterplate and pull the fuel line off the car-buretor. Take out the two pan headscrews. Lift out the carburetor anddisconnect the throttle cable from thelever on the throttle shaft - this is bestdone with the throttle shaft in the full-throttle position; the same applies forreassembly.

There is a gasket at both sides of thediaphragm, between the carburetorand crankcase flange. Replace thesegaskets when installing the carbu-retor. Coat the sealing faces with alittle jointing paste, taking care not tocover the pulse bore.

It is still necessary to unscrew and liftthe carburetor even if only the throttlecable is faulty.

1. The inlet needle is not sealing(foreign matter in valve seat orcone of inlet needle is damaged).

2. The metering diaphragm is dama-ged.

In either of these cases the carbure-tor must be removed and repaired. Itis necessary to unscrew the carbure-tor mounting screws and raise thecarburetor in order to refit the fuelline.

The carburetor can be tested forleaks with the carburetor andcrankcase tester 1106 850 2900.

First remove the filter cover and filterplate and disconnect the fuel linefrom the elbow connector. As theinside diameter of the test hose islarger than the outside diameter ofthe elbow connector, a fuel line(1120 358 0700) must be used asan adapter to make the connection.

Push one end of the fuel line onto theelbow connector and the other endinto the test hose.

Now close the vent screw on therubber bulb and pump air into thecarburetor until the pressure gaugeindicates a pressure of 0.4 to 0.5 bar.

If this pressure remains constant, thecarburetor is airtight. However, if itdrops, there are two possible causes:

Bottom:Tester connected Correct position of fuel line Removing the carburetor

STIHL 009, 010, 011 48

8.5 Repair of Carburetor

It is advisable to check the service-ability of the fuel pump whenever thecarburetor is removed for repair.

Unscrew the fuel pump end cover andremove the gasket and pumpdiaphragm. The end cover, gasketand diaphragm are frequently stucktogether. If this is the case, take parti-cular care when separating them. Ifthe fuel strainer in the pump side ofthe carburetor body is dirty, it should

be lifted out with a screwdriver andwashed in clean gasoline. Alwaysreplace the fuel strainer if it showsany signs of damage.

To disassemble the carburetor body,unscrew the metering chamber coverand remove the metering diaphragmand gasket. This diaphragm and gas-ket may also be stuck together andmust be separated carefully.

The diaphragms are the mostdelicate parts of the carburetor. Dueto the continuous alternating stressto which the diaphragms aresubjected, the material eventuallyshows signs of fatigue - thediaphragms distort and swell. Whenthis stage is reached the carburetorcan no longer function correctly andthe diaphragms must be replaced.

The inlet needle valve is located in a

recess in the metering diaphragmchamber. The inlet control lever withspindle, helical spring and inletneedle can be removed afterunscrewing the round head screw. Ifan annular indentation is visible onthe cone of the inlet needle, it shouldbe replaced as it will no longer sealproperly. This is indicated byconstant flooding of the carburetoralthough the needle is clean.

Top:Removing fuel pump end cover

Bottom:Taking out the fuel strainer Removing metering chamber cover Removing inlet needle

STIHL 009, 010, 011 49

Top: Top:Removing adjustment screws Locating studs on carburetor body

Bottom: Bottom:Removing the plate Hole in metering chamber cover Locating studs on end cover

end cover must face away from theadjustment screws.

Refit the fuel strainer, pump dia-phragm, gasket and fuel pump endcover and screw down firmly. Thetwo integrally cast studs on the endcover locate the pump diaphragmand gasket.

annular groove on head of inletneedle and secure it with thecountersunk screw, making sure thehelical spring locates on the controllever's dimple. Check freedom ofmovement of inlet control lever.

Now screw the two adjustmentscrews and plate into position.

Then fit and secure the gasket, mete-ring diaphragm and the end cover onthe carburetor body. The hole in the

Wash all parts of the carburetor inclean gasoline (never use highoctane gasoline) and blow out withcompressed air, paying particularattention to the bores and ports.Remove the two adjustment screwsas well as the plate and gasket(countersunk screw) for this purpose.

After cleaning the carburetor, insertthe inlet needle and fit the helicalspring in its bore. Position spindle ininlet control lever, engage clevis in

STIHL 009, 010, 011 50

8.6.1 Notes for Fine Adjustmentof Carburetor

Adjusting idle speed screw(Filter cover must be removed for thisadjustment)

Do not interchange these adjustmentscrews!

Always carry out carburetor adjust-ments with the engine warm and theair filter clean.

Engine stops while idling:

Turn idle speed screw slightly clock-wise (to the right) while the engine isrunning (chain must not rotate).

Chain rotates at idle speed:

Turn idle speed screw slightly coun-terclockwise (to the left).

Engine runs erratically at idlespeed:

Regulate at low-speed adjustmentscrew. Turn clockwise for leaner mix-ture or counterclockwise for richermixture.

Important: Even very slightalteration of the adjustment screwsettings has a marked effect onengine running characteristics.

The carburetor is adjusted at the fac-tory to provide optimum enginepower and low fuel consumptionunder local atmospheric conditions.

If the chain saw is operated at highaltitudes (mountains) or near sealevel, the carburetor setting must bealtered. This correction is made atthe two adjustments screws and theidle speed screw.

Both adjustment screws must be verycarefully screwed down onto theirseats in order to obtain the basic set-ting which is only intended as a guidefor fine adjustment. Then adjust asfollows:

High-speed adjustment screw H:Long, open 1 turn

Low-speed adjustment screw L:Short, open 1 turn

1 = High-speed adjustment screw2 = Low-speed adjustment screw3 = Idle speed screw

STIHL 009, 010, 011 51

The diaphragm pump draws fuel outof the fuel tank and into the carburetorvia the fuel line. Any impurities mixedwith the fuel in the tank are filtered outby the pickup body (filter and felt bar).The fine pores of the felt bareventually become blocked withminute particles of dirt. This restrictsthe passage of fuel and the result isfuel starvation.

In the event of trouble with the fuelsupply system, always clean the filterin the pickup body first. To do this,pull the pickup body out through thetank filler.

The felt bar can now be taken out ofthe pickup body and replaced. Whenreinstalling the pickup body, makesure it is positioned at the lowest pointin the tank.

It is not advisable to clean the felt bar- always fit a new one.

Trouble-free operation of thecarburetor depends on the fuel tankand atmospheric pressures alwaysbeing equal. This is assured by the

The tank vent consists of a tube and agrub screw. When replacing the tankvent, push grub screw into the tube,slotted end first, until its tip is flushwith the end of the tube.

Then insert tube about 8 mm in itshousing bore with the tip of the grubscrew facing the carburetor chamber.

In the event of difficulties with thecarburetor or fuel supply system,always check and clean the tank vent.If the thread of the grub screw has cutdeeply into the tube, replace the venttube.

Withdrawing the pickup body Removing the felt bar Tank vent in position

8.7 Fuel Line 8.8 Tank Vent

STIHL 009, 010, 011 52

Top:Choke slide in "CHOKE" position

Bottom:Removing filter cover Pressing down the valve plate

8.9 Air Filter and Choke Valve

The air filter's function is to interceptand retain dust and dirt in the intakeair and thus reduce wear on enginecomponents.

Clogged air filters have a detrimentaleffect on engine performance, theyincrease fuel consumption and makestarting more difficult.

Clean loose dirt off the filter coverand the surrounding area beforeremoving the filter to insure that noforeign matter can get into thecarburetor or engine when the filtercover is lifted off.

The filter can then be knocked outand cleaned with gasoline. It mayalso be blown out with compressedair. In the case of a repair it is alwaysbest to fit a new filter.

Use this opportunity to check thecondition and operation of the chokevalve.

A faulty choke valve can be removedwithout tools. To do this, move chokeslide to "CHOKE". Then press valveplate down against the spring withyour thumb and pull slide downwardand turn it through 90° at same time.

Installation is a reversal of the abovesequence.

Stihl 09 010 011 Workshop Manual - The Bakelite Radio -...

Documents

Transcript of Stihl 09 010 011 Workshop Manual - The Bakelite Radio -...