3-15
Fuel System
3-15
DISASSEMBLY
Replace the float if it leaks or if the assembly is
Use a separate container for the component parts of
damaged in any way. Replace the main body if the protective
the sub-assemblies to facilitate cleaning, inspection, and
plating is damaged exposing bare metal to corrosion. Check
assembly.
the action of the poppet valve in the choke plate, and free it up
1.
Remove the accelerator pump link cotter pin and
if necessary. Replace the choke lever and shaft assembly if
slide the upper end of the link out of the pump
the threads in the shaft are stripped or if it is not securely
operating lever. Remove the two throttle body screws
riveted to the lever.
and lock washers. Separate the throttle body and
ASSEMBLY
main body, and remove the gasket.
Always install new gaskets when rebuilding the
2.
Remove the fuel inlet fitting with a box wrench, and
carburetor. A carburetor overhaul kit is available for service.
remove the gasket. Remove the four float bowl
A disassembled view of the carburetor is shown in Figure 32.
retainer screws, lockwashers, and clamps. Remove
1.
Install the pump link in the throttle lever, then secure
the retainer, retainer gasket, float bowl, and bowl
it with a cotter pin. Install the idle adjusting needle
gasket.
and spring. Turn the needle in gently with the fingers
3.
Remove the fuel inlet seat screw and gasket located
until it seats, then back it off 1/2 turns for a
in the fuel inlet opening. Remove the fuel inlet needle
preliminary idle adjustment. To avoid grooving the tip
valve and float assembly, and the gasket from inside
of the needle, do not force the needle against its seat.
the main body. Remove the float shaft, releasing the
2.
Install the distributor passage ball and ball retainer.
float. Slide the fuel inlet needle assembly off the float
Place the choke bracket in position on the main body
lever tab. Remove the wire clip, spring, and plunger
and install the choke bracket screw and lockwasher.
from the fuel inlet needle. Remove the three power
Insert the choke plate and valve assembly into the
valve diaphragm screws and lockwashers, then lift
main body. The poppet valve stem should be
the power valve diaphragm and stem assembly out of
pointing down. Install the main discharge nozzle.
the main body.
Separate the cover from the
Slide the choke shaft in position and install, but do
diaphragm and stem assembly.
not tighten. the choke plate screw. Close the choke
4.
Remove the five main well screws and lock washers,
plate and hold the main body up to the light. Little or
then remove the main well. Remove the pump return
no light should show between the choke plate and the
spring from the metal disc on the accelerating pump
walls of the bore. Make sure the choke plate does
piston. then remove the spacer gasket. Pull the
not bind, then tighten the choke plate screw. Install
accelerating pump diaphragm out of the main body.
the choke shaft locating screw and lockwasher.
Remove the pump operating lever retainer, then slide
3.
Place the pump operating lever on the stud in the
the lever off the stud. Remove the choke bracket
main body, and fit the pump operating lever retainer
screw and lockwasher. the choke plate screw and
on the stud. Place the spring on the pump diaphragm
lockwasher, and the choke shaft locating screw and
rod, and press the pump rod sleeve into the rod to
lockwasher.
Slide the choke shaft and lever
compress the spring. Drop the pump rod sleeve
assembly out of the main body, then remove the
retainer ball into the hole in the sleeve. Be sure the
choke bracket. Slide the main discharge nozzle out
main discharge nozzle gasket is in place in the main
of the main body, then remove the choke plate and
body, then position the pump assembly in the main
valve assembly. Invert the main body and remove
body. Place the main well spacer gasket, over the
the distributor passage ball retainer and the
pump assembly.
distributor passage ball.
4.
Insert the pump inlet check ball, and the pump outlet
5.
Remove the main jet, the pump inlet check valve
check ball in the main well body. The pump inlet
retainer, and the pump discharge valve retainer from
check ball is slightly larger than the pump outlet
the main well body. Invert the body, allowing the
check ball. Be sure they are installed in their proper
pump inlet check ball, pump outlet check ball weight
chamber. Seat the check balls with one gentle tap of
and check ball to fall out into the hand.
a light hammer and a soft brass drift. Be sure the
6.
Press the pump rod sleeve toward the diaphragm
check balls move freely in their chambers, then install
until the pump rod sleeve retainer ball drops out.
the pump inlet check ball retainer, and the outlet
Remove the pump rod sleeve and spring.
check ball weight and retainer. Install the main jet in
7.
Remove the idle adjusting needle and spring.
the main well body.
Remove the pump link cotter pin and link.
5.
Seat the large end of the pump return spring in the
On carburetors equipped with a dashpot, remove the
metal disc on the accelerating pump diaphragm.
dashpot lever.
Position the main well body screws and lock washers
At times it may be necessary to remove the throttle
in the body. The two long screws are placed in the
plate and shaft to accomplish a thorough cleaning job. If this
center top and center bottom holes; the short screws
is done, be sure to mark the throttle plate before removal so it
are used in the three remaining holes. Insert the
can be installed in exactly the same position. Throttle plates
power valve end of the main well body into the main
and shafts cannot be interchanged between carburetors, nor
body, then press the main well body into position
are they serviced as separate parts.
against the spacer gasket as follows:
CLEANING AND INSPECTION
Apply pressure with the index finger against the
Many carburetor troubles are the result of deposits
protruding end of the pump rod sleeve, to fully compress the
accumulating in the carburetor. A thorough cleaning must be
pump return spring, as the thumb presses the main well body
performed to assure satisfactory carburetor performance.
into position.
This will prevent the pump return spring
CLEANING
pressure from disturbing the alignment of the holes in the
Soak all castings and metal parts in a cleaning solution to
diaphragm, spacer gasket, and main body. Before releasing
soften and loosen all foreign deposits. If a commercial
the pump rod sleeve, tighten the five main well body screws.
carburetor cleaning solvent is not available, lacquer thinner or
6.
Position the power valve gasket, power valve
defatured alcohol may be used.
diaphragm stem assembly, and the power valve body
cover in the main body. Install the three power valve
INSPECTION
body cover screws and lockwashers.
