TM 5-4320-218-15
f. Put the pump bracket in a vise. Line up
back and forth several strokes, releasing it with
the file mark on the edge of the bracket with
a snap. The pump is now fully assembled and
the file mark on the edge of the fuel head.
ready for service.
Get the diaphragm flush by moving the rocker
arm, and hold it flush while installing all the
g. Install the fuel pump and the fuel pump
s c r e w s and lockwashers. Be sure that the
adapter in place on the engine. Start the en-
screws pass through the holes in the diaphragm
gine and observe the operation of the fuel
easily without damaging the fabric. Tighten
pump. Check for leaks; tighten any loose con-
them evenly and securely. Push the rocker arm
nections.
Section IV. CARBURETOR
85. Description
87. Carburetor Cleaning and Inspection
The carburetor is a horizontal, single-venturi
a. Clean all the metal parts in an approved
cleaning solvent and dry each part thoroughly.
type with a straight-through air intake. The
float chamber is constructed concentric with the
b. Blow out all passages in the throttle
main discharge jet, thereby practically sur-
body and fuel bowl with clean, dry compressed
rounding the main metering system with fuel.
air. Reverse the flow of air in the passages to
insure that all dirt has been removed. Make
This design permits a supply of gasoline to be
sure that all carbon deposits and other foreign
present at the main discharge jet, even when
matter have been removed from the throttle
the engine is at an angle. The float assembly is
bore and idle port.
of the dual type and is so constructed that one
float operates in each side of the float chamber.
The dual floats are connected to the float
c. Inspect the top side of the float for wear
needle valve by a single lever.
where it contacts the fuel-valve needle. Replace
the float if it is loaded with fuel or damaged,
a. Remove the carburetor from the engine.
if its axle bearing is worn, or if its top surface
shows wear.
b. Loosen the screw (16) and screw (20) and
d. Replace the float axle if it is visibly worn
disconnect the choke control (25) from choke
or bent.
swivel (17).
e. Examine the idle adjusting needle, and re-
c. Invert the carburetor body (9) with the
place it if its point is rough or damaged.
fuel bowl (30) facing up. Remove the bowl
f. Inspect the throttle plate and the choke
retaining plug (31) and gasket (26). Remove
plate; replace if rough or if the edges are dam-
the bowl (30) and gasket (29).
aged.
d. Remove the float lever shaft (24) and lift
g. Check the bearing surfaces of the choke
off the float (28). Lift out the valve (27)
shaft and throttle shaft for wear; replace if
from its seat.
e. Use a screwdriver of the proper size and
worn.
h. Whenever the carburetor is disassembled,
remove the valve seat (27) and gasket (26). Re-
move the main nozzle (32) and gasket (33).
replace the fuel valve and seat and all gaskets
and fiber washers.
f. Turn the choke shaft until the screws (19)
i. Rebush the carburetor body to provide a
can be removed. Remove the screws (19) and
close fit for the throttle shaft, as follows:
pull out the choke fly (18) and choke shaft
(1) Place a suitable center in the drill
(14) from the body (9). Remove the screws
p r e s s bed. With one throttle-shaft
(20 and 12) and remove the choke bracket as-
hole on this center, bring the spindle
sembly (21).
down until the counterbore reamer
g. Remove the screws (1) and remove the
contacts the opposite shaft hole. The
throttle fly (2). Slide the throttle shaft assem-
reamer provides a press fit for the
bly (5) from the body (9).
