Section III. REPAIR OF ENGINE FUEL SYSTEM

(d) Install radiator cap, then test radiator

receive silver solder, solder leaks, then solder heat

exchanger to bottom of radiator core.

core. Do not exceed 10 psi of controlled air pressure.

(3) Test.

(e) When leak is evident in radiator,

(a) Use controlled air pressure.

repair radiator as in d(1) above. Replace a radiator,

(b) Plug one port of heat exchanger,

when heat exchanger or radiator core is beyond repair.

apply air pressure to the remaining port, then gradually

increase pressure to 30 psi.

exchanger as in d(2) above.

Section III. REPAIR OF ENGINE FUEL SYSTEM

(h) Remove the two screws (57)

3-7. General

attaching throttle plate (56) to throttle shaft and remove

This section will cover direct and general support

plate.

maintenance of the engine fuel system authorized by the

(i) From governor end of throttle shaft,

maintenance allocation chart, and includes the

remove cotter pin (2) and retainer (3); slide governor

carburetor, governor, and fuel tank.

lever (5) and spring (4) off shaft (48). Note position of

3-8. Carburetor

spring and lever to insure correct reassembly.

a. Description. The carburetor is mounted directly)

(j) Drive roll pins (55) from shaft.

to the intake manifold on the left side of the engine. The

(k) Pull throttle shaft with lever from

throttle valve is controlled by the action of the accelerator

throttle body. If is not necessary to remove throttle lever

controls and the action of a variable speed governor. It

from shaft unless the parts must be replaced.

is of the single venturi, updraft type which mixes the

(l) Remove both throttle shaft seals (9

correct proportions of air and fuel to produce a highly

and 46) and retainers (8 and 47) using end of a small

combustible mixture, which is then drawn into the intake

screwdriver to lift out parts.

manifold. All mixture adjustments, except idle, are

(3) Disassembly fuel bowl body as follows:

controlled by fixed jets. The idle fuel adjusting screw

(a) Remove drain plug (35) from bottom

controls the fuel mixture for the idle system.

of fuel bowl body.

The idle throttle stop screw controls low engine rpm.

(b) Remove passage plug (33) and fibre

The air intake of the carburetor is provided with a choke

washer (34) from bottom of fuel bowl body.

valve as an aid in starting a cold engine.

b. Removal. Refer to TM 10-3930-618-20.

washer (31) from passage in bottom of fuel bowl body.

c. Disassembly.

(d) With a small screwdriver, remove

(1) Separate carburetor bodies as follows:

well vent jet (42) from center of large opening in

(a) Remove the four screws (15, fig. 3-

machined surface of fuel bowl.

7) and lockwashers which attach throttle body ( 11 to

(e) Remove main jet (28) and fibre

fuel bowl (30).

washer (29) from inside fuel bowl.

(b) Separate throttle body from fuel

(f) Note position of choke bracket (27)

body and remove gasket.

and choke shaft (24) to insure correct reassembly.

(2) Disassemble throttle body as follows:

(g) Remove choke plate screws (39)

(a) Press screwdriver against the float

and lockwashers.

axle (21) at slotted side of float hinge bracket and force

(h) Remove choke plate (38), choke

axle through hinge bracket.

(b) Pull float axle out from opposite side

shaft (24) and lever.

(i) choke bracket by removing the two

and remove float (20).

capscrews (26).

(j) Drive out choke shaft hole plug (37)

and waster , (16) from throttle body.

(d) Remove venturi 1191.

by using a short length of -inch rod inserted through

opposite shaft hole.

(e) Remove idle jet (44) from its

(k) Remove shaft seals (40) by using

passage near float valve seat.

end of a small screwdriver to lift out parts.

(f) Remove idle adjusting needle (13)

d. Cleaning and Inspection.

and spring (12) from front of throttle body.

(1) Clean all metal parts thoroughly in an

(g) Unscrew throttle stop screw (54)

approved cleaning solution, then rinse in cleaning solvent

until threaded end is flush with the lever (51).

(Spec. P-S-661).

3-8