Post on 11-Mar-2018
Remove Carburetor
Remove Air Cleaner
Models 235400, 245400
1. Remove air cleaner knobs and cover.
2. Remove cartridge, pre-cleaner and pre-cleaner filter
retainer.
3. Remove hex. Screw from lower right hand corner of
air cleaner base.
4. Remove two (2) hex. Nuts and fuel spray shield.
5. Remove air cleaner base and air cleaner gasket.
Disconnect breather tube from air cleaner base.
Remove Air Cleaner
Models 287, 28N thru W, 310/312/313700
1. Remove air cleaner cover knob and cover.
2. Remove cartridge knob and cartridge with
pre-cleaner.
3. Push breather tube down out of air cleaner base.
4. Remove upper screw from air cleaner brace and
loosen lower screw.
5. Remove screw from air cleaner base and remove
two (2) nuts holding air cleaner base to carburetor
intake, Fig. 185.
CARBURETION
Large Walbro LMT Carburetors
Remove
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 1 of 2
Fig. 185 - Remove Air Cleaner
Models 287, 28N thru W, 310/312/313700
Remove Carburetor
Models 235400, 245400
1. Remove knob from throttle control lever.
2. Remove screw holding panel to front control bracket
at carburetor.
3. Remove screw from fuel tank bracket or support
bracket.
4. Remove two hex. screws holding choke control
bracket to governor control bracket, Fig. 186.
5. Slide choke control bracket and carburetor out to end
of carburetor mounting studs. Lift choke control
bracket to clear choke shaft and remove.
6. Remove air cleaner gasket and continue to pull
carburetor off studs until clear of studs.
7. Disconnect link spring from throttle lever and then tip
carburetor over to disengage Z-bend of throttle link
from throttle lever.
Remove Carburetor
Model 287, 28N thru W, 310/312/313700
1. Disconnect wire(s) from carburetor solenoid.
2. Remove two (2) carburetor studs while holding
carburetor.
3. Pull carburetor away from governor control bracket
and rotate carburetor to disengage Choke-a-Matic®
linkage, governor link, and governor link spring from
carburetor, Fig. 188.
CARBURETION
Large Walbro LMT Carburetors
Remove
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 2 of 2
Fig. 186 - Removing Choke Control Bracket
Fig. 188 - Remove Carburetor
Disassemble Carburetor
Models 235/45, 287, 28N thru W, 310/312/313700
1. Remove solenoid and fuel bowl washer.
Note: Models 235400, 245400 do not use
solenoids.
Note: Two (2) styles of solenoids have been used.
Early style had one (1) wire, (RED) connected
to the bottom of the solenoid. The current style
has been made in two (2) versions. However,
both have a two (2) wire connector (GRAY for
solenoid & BLACK, for solenoid ground) on the
side of the solenoid. The early version can only
be removed with an automotive 1/2" tappet
wrench while the late version can be removed
with a regular 1/2" open end wrench.
2. Remove float bowl and float bowl gasket from
carburetor.
3. Remove float hinge pin, float, and inlet needle.
4. Remove idle mixture screw limiter cap, when used.
5. Rotate throttle shaft and lever to closed position and
remove two (2) throttle plate screws.
6. Remove throttle plate, throttle shaft with lever, and
foam seal.
7. Remove throttle shaft seal or bushing from carburetor
body.
Choke Shafts
These carburetors are equipped with two styles of
choke shafts:
1. Plastic shaft with snap in choke plate or;
2. Metal shaft with screw mounted choke plate.
Remove Plastic Choke Shaft & Plate
1. Rotate choke shaft to wide open position.
2. Pull choke plate out of choke shaft and lever.
3. Remove choke shaft and lever, return spring (when
used), and foam washer.
CARBURETION
Large Walbro LMT Carburetors
Disassemble
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 1 of 3
Fig. 189 - Solenoid Types
Disassemble Carburetor
Models 235/45, 287, 28N thru W, 310/312/313700
Remove Metal Choke Shaft & Plate
1. Rotate choke shaft and lever to closed position.
Service replacement carburetors may have a spring
detent that will hold choke in closed position.
2. Hold choke closed and remove two (2) screws
holding choke plate.
3. Remove plate. Release tension on choke shaft and
remove choke shaft and lever, return spring and seal
assembly.
4. Remove brass pilot jet (with type numbers not ending
in A1 or E1) from carburetor body, Fig. 190.
5. Using Tool #19062, Carburetor Jet Screwdriver,
remove emulsion tube, Fig. 191.
6. With a modified 5/16 inch (3.9 mm) pin punch, remove
welch plug from carburetor body, Fig. 192.
CARBURETION
Large Walbro LMT Carburetors
Disassemble
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 2 of 3
Fig. 190 - Remove Pilot Jet
Fig. 191 - Remove Emulsion Tube
Fig. 192 - Remove Welch Plug
Remove Fuel Inlet Seat
1. Use self-threading screw Part #93029 from Tool
#19165, Flywheel Puller, or 1/4-20 tap.
2. Thread screw or tap into fuel inlet seat 3-4 turns
and remove, Fig. 193.
3. Place 1/4" x 20 nut and washer, onto puller screw.
4. Place a 1/4" drive 3/8" socket over fuel inlet seat.
5. Thread screw into tapped inlet seat until screw
bottoms.
6. Thread nut down unto washer and continue turning
nut until inlet seat is free from carburetor body,
Fig. 194.
CARBURETION
Large Walbro LMT Carburetors
Disassemble
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 3 of 3
Fig. 193 - Threading Or Tapping Fuel Inlet Seat
Fig. 194 - Remove Fuel Inlet Seat
Test Solenoid, Current Style
1. Insert jumpers in connector on side of solenoid.
2. Test solenoid by connecting jumpers to a new 9 volt
transistor battery.
3. Plunger needle should snap into solenoid body.
If not, replace.
Test Solenoid, Early Style
1. Test solenoid by connecting jumper from positive post
of a new 9 volt transistor battery to solenoid terminal.
2. Then touch body of solenoid to negative post of
battery. Plunger needle should snap into solenoid
body. If not, replace.
CARBURETION
Large Walbro LMT Carburetors
Test Anti-Afterfire Solenoid
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Install Welch Plug
1. Install welch plug with pin punch slightly smaller than
outside diameter of plug. Press in until plug is flat.
Do not cave in plug.
2. After plug is installed, seal outside edge of plug with
fingernail polish or non-hardening sealant, Fig. 195.
3. Using Tool #19135, Knockout Pin, press new fuel inlet
seat in until flush with fuel inlet boss, Fig. 196.
Install Metal Choke Shaft
1. Install foam seal and return spring on choke shaft
hooking small hook in notch on choke lever,
Fig. 197, inset.
2. Insert choke shaft assembly into carburetor body
and engage large end of return spring on boss.
3. If carburetor has spring detent, guide detent spring
into slot on choke shaft lever, Fig. 197.
4. Place choke plate on shaft with single notch on edge
towards fuel inlet. Two (2) half moon dimples will help
to position plate on shaft.
CARBURETION
Large Walbro LMT Carburetors
Assemble
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 1 of 4
Fig. 195 - Install Welch Plug
Fig. 196 - Install Fuel Inlet Seat
Fig. 197 - Install Metal Choke Shaft
Install Plastic Choke Shaft
Models 235400, 245400
1. Place foam seal on choke shaft.
2. Install choke shaft and seal in carburetor and turn
shaft clockwise as far as it will go.
3. Install choke plate with number facing towards detent
spring. Rotate choke shaft to center choke plate,
Fig. 198.
1. Insert spring inside large foam seal and slide seal and
spring onto choke shaft with straight end of spring up
toward choke shaft lever.
2. Insert choke shaft into carburetor body until hook of
spring hooks on spring anchor.
3. Lift choke shaft and lever up slightly and turn
counterclockwise until stop on lever clears spring
anchor and push shaft down, Fig. 199.
4. Insert choke plate into choke shaft and lever with
dimples toward fuel inlet side of carburetor.
Dimples help to hold and align choke plate on shaft,
Fig. 199.
CARBURETION
Large Walbro LMT Carburetors
Assemble
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 2 of 4
Fig. 198 - Install Choke Shaft
Fig. 199 - Install Plastic Choke Shaft
Install Throttle Shaft
Models 235400, 245400
1. Install throttle shaft bushing in carburetor.
2. Slide foam seal onto throttle shaft.
3. Slide throttle shaft and seal into carburetor making
sure idle stop on throttle lever is to left of idle speed
screw.
4. Rotate throttle shaft clockwise until idle stop is
against idle speed screw.
5. Place throttle plate on throttle shaft with numbers
facing into carburetor and to the right.
6. Place a drop of Loctite® on screw threads and
tighten, Fig. 200.
Note: On Model 235400, throttle plate
movement is limited and will not go to the wide
open position. This is normal.
Install Throttle Shaft
Models 287, 28N thru 28W, 310/312/313700
1. Install throttle shaft seal with sealing lip down in
carburetor body until top of seal is flush with top of
carburetor.
2. Install throttle shaft and small foam washer.
Turn shaft until flat is facing out.
3. Lay throttle plate on shaft with numbers toward idle
mixture screw and dimples facing in resting on edge
of shaft. Install two (2) screws, Fig. 201.
Install Emulsion Tube
1. Install emulsion tube using Tool #19062, Carburetor
Jet Screwdriver, until emulsion tube seats, Fig. 202.
2. After installing emulsion tube, use compressed air to
blow out any chips or debris that may have been
loosened while installing emulsion tube.
Note: On Models 287, 28N thru W, 310/312/313700,
install main jet only after installing emulsion tube.
CARBURETION
Large Walbro LMT Carburetors
Assemble
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 3 of 4
Fig. 200 - Install Throttle Shaft
Fig. 201 - Install Throttle Shaft
Fig. 202 - Install Emulsion Tube
Install Inlet Needle & Float
1. Insert inlet needle valve in slot on float.
2. Place float and needle on carburetor and install float
hinge pin centering hinge pin.
3. Place bowl gasket on carburetor body.
4. Place bowl on carburetor and install solenoid and
float bowl washer torquing solenoid to 45 In. Lbs.
(5 Nm).
Install Idle Screw and Pilot Jet
Install pilot jet (with type numbers not ending in A1 or
E1) until it seats securely. Install idle mixture screw with
spring and turn until head of screw touches spring.
CARBURETION
Large Walbro LMT Carburetors
Assemble
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 4 of 4
Fig. 202a - Install Inlet Needle - Typical
Install Carburetor
Models 235400, 245400
Install Spacer
Place an intake gasket next to cylinder head, the
carburetor spacer, and a second intake gasket. Both
gaskets have round holes.
1. Hook "Z" bend of governor link into nylon bushing of
throttle lever. Then hook link spring into hole of throttle
lever.
2. Slide carburetor unto carburetor studs until front of
carburetor is flush with end of studs.
3. Place one (1) air cleaner gasket (gasket with two (2)
notches in inside diameter) on carburetor mounting
studs.
4. Install choke control bracket on carburetor making
sure alignment pin on choke shaft is engaged in hole in
control plate, Fig. 203.
5. Place new carburetor mounting gasket on studs and
slide on air cleaner base, fuel spray shield and install
two (2) nuts and one (1) screw to secure air cleaner
base, Fig. 204. Torque nuts and screw to 45 In. Lbs.
(5 Nm).
6. Place fuel spray shield on carburetor studs and install
two (2) hex. nuts. Then install hex. screw in lower
right hand corner of air cleaner base to air cleaner
brace. Torque nuts and screw to 45 In. Lbs. (5 Nm)
7. Assemble pre-cleaner, retainer, and air cleaner
cartridge. Insert tabs on cover in slots of air cleaner
base and close air cleaner cover assembly and
tighten air cleaner knobs, Fig. 205.
8. Install fuel hose and clamp on carburetor inlet.
CARBURETION
Large Walbro LMT Carburetors
Install
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 1 of 3
Fig. 203 - Install Choke Control Bracket
Fig. 204 - Install Air Cleaner Base
Fig. 205 - Install Air Cleaner Cover Assembly
Install Control Panel
9. Install control panel and torque screw holding bracket
to choke control plate to 45 In. Lbs. (5 Nm). Install
screw holding control panel to fuel tank bracket or
support bracket to 45 In. Lbs. (5 Nm), Fig. 206.
Install Carburetor
Models 287,28N thru W, 310/312/313700
Install Intake Manifold
If carburetor intake was removed, place new gasket
and manifold on intake port and torque screws to
100 In. Lbs. (11 Nm), Fig. 207.
Install Governor Link & Spring
1. Place two (2) studs on carburetor and new gasket on
studs with long edge on side of gasket opposite fuel
inlet.
2. Hook governor link spring in throttle lever hole without
grommet.
3. Hook governor link in throttle lever hole grommet with
link on top of lever, Fig 208.
CARBURETION
Large Walbro LMT Carburetors
Install
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 2 of 3
Fig. 206 - Installing Control Panel
Fig. 207 - Install Intake Manifold
Fig. 208 - Install Governor Link & Spring
Install Choke-a-Matic® Link & Carburetor
1. Insert "U" bend of Choke-a-Matic® link in outer hole of
choke lever from bottom of lever.
2. Slide "U" bend of link into slot on governor control
bracket and place carburetor on intake elbow.
Torque studs to 90 In. Lbs. (8 Nm), Fig. 209.
3. Install air cleaner body and torque nuts to 60 In. Lbs.
(6 Nm). Install screw inside air cleaner body.
4. Install breather tube in air cleaner body opening.
5. Install air cleaner brace.
CARBURETION
Large Walbro LMT Carburetors
Install
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 3 of 3
Fig. 209 - Install Carburetor
1. Start and run engine for 5 minutes at 1/2 throttle to
bring engine up to operating temperature.
2. Move equipment control to idle position.
3. Turn idle speed screw to obtain 1750 RPM Minimum.
4. Turn idle mixture screw slowly clockwise until engine
just begins to slow.
5. Turn screw opposite direction until engine just begins
to slow. Turn screw back to midpoint.
6. Install limiter cap with flat facing up, (when so
equipped), Fig. 210.
Note : If engine is adjusted for governed idle, reset idle
speed screw to 1200 RPM. For governed idle
adjustment procedure see Governors.
7. Move equipment speed control from idle to high speed
position. Engine should accelerate smoothly. If it does
not, open idle mixture needle screw 1/8 turn open.
There should be no afterfire.
CARBURETION
Large Walbro LMT Carburetors
Adjust
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Fig. 210 - Install Limiter Cap
Fuel Pump
The fuel pump, mounted near the blower housing and
the air cleaner cover, allows remote fuel tank
installations on Models 161400, 260700, and 261700
engines. The pump is operated by vacuum pulses from
the engine.
1. Install two (2) screws and nuts in fuel pump and
mounting bracket.
2. Connect vacuum line and fuel lines to the fuel pump,
Figs. 211 and 212. Hose clamps must retain hoses
securely.
3. Start engine and inspect fuel pump and hose
connections for leaks.
Inline Fuel Filter Service
Inline fuel filter should be checked yearly or every 100
hours of operation.
Replace filter if dirt or water are present. We
recommend that filter, Part #394358 (fuel pump), Part
#298090 (gravity feed), or Part #492836 (special
purpose) be added to engine not so equipped.
Note: Inline fuel filters supplied by Briggs & Stratton
can be installed without regard to marking on
filter (in, out).
However, if filter is removed, install with flow in same
direction as removed. If in doubt, use new filter.
CARBURETION
Large Walbro LMT Carburetors
Fuel Pumps - Filters - Tanks
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 1 of 2
Fig. 211 - Typical Hose Routing - Models 260700, 261700
Fig. 213 - Fuel Filter
Fig. 212 - Typical Hose Routing - Model 161400
Fuel Tank
Inspect Fuel Tank
Inspect fuel tank for cracked or leaking seams. Inspect
fuel fill filter (optional) and inline filter for dirt, debris or
gum deposits, Fig. 213. Replace fuel tank if it leaks.
Fuel Shut-Off Valve
Description
The fuel shut-off valve allows stopping of fuel flow to
the carburetor. The carburetor can then be drained for
short term storage or removed for servicing.
Inspect valve for ease of operation and leakage.
Replace if operation is difficult or valve will not shut off
fuel flow or leaks externally, Fig. 214.
Disassemble Fuel Shut-Off Valve
Rotate handle to on position and remove two (2) phillips
screws. Rotate valve and pull out. Remove retainer and
O-Ring.
Inspect Fuel Shut-Off Valve
Check valve body for cracks or corrosion. Replace
valve, if damaged. Check O-Ring for brittleness, cuts or
flat spots. Replace if damaged.
Assemble Fuel Shut-Off Valve
If valve retainer was removed reinstall on valve handle
with indentations toward O-Ring. Moisten O-Ring with
engine oil or gasoline and insert into valve body. Install
two (2) phillips screws and tighten.
CARBURETION
Large Walbro LMT Carburetors
Fuel Pumps - Filters - Tanks
Single Cylinder OHV Engine Repair ManualVersion 1.0
Copyright© 1999 by Briggs and Stratton Corporation
Page 2 of 2
Fig. 214 - Fuel Valve