TM 5-4310-335-14
Table 5-1. TROUBLESHOOTING (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
d. Remove screw (2) and remove air cleaner duct elbow from carburetor.
e. Remove screw (2) and remove throttle housing from carburetor. Remove rear cover and gaskets from
throttle housing.
f. Spread control rod clevis and remove throttle lever.
g. Remove screw and remove throttle control from carburetor.
remove the line from air cleaner to cylinder head. Remove the rocker arms, cylinder head, pushrods, and
pushrod housing as follows:
a. Remove nuts (4).
b. Remove clip and slide shaft from cylinder head.
c. Remove nut and adjusting screw.
d. Remove push rod housing.
NOTE
Remove push rods and packing from housings.
e Remove cylinder head.
NOTE
Remove and discard cylinder head gasket.
NOTE
Remove needle bearings from rocker arm shaft.
WARNING
Dry cleaning solvent, P-D-680 or P-S-661, used to clean parts is potentially
dangerous to personnel and property. Avoid repeated and prolonged skin
contact. Do not use near open flame or excessive heat. Flash point of
solvent is 100 (39 ) - 138 (59 ).
F
C
F
C
Inspect parts for defects, damage, cracks, breaks, deterioration, warps and dents. Remove carbon deposits,
grease, other materials or gum. Remove any burrs or nicks. Clean parts with dry cleaning solvent P-D.680.
Dry parts thoroughly with compressed filtered air and place on clean shop towels' or cloths and tag. Replace
parts if damaged or defective with standard replacement parts or equivalent. Check the valve springs for proper
tension. Replace a damaged or defective valve spring.
NOTE
The valve springs should test to the following dimensions:
Free length
1.275 in.
Load at compressed length of 1.095 in. = 20 lbs 1 lb.
Load at compressed length of 0.880 in. = 44 lbs 2 lbs.
Grind valves and lap them to the seat inserts individually to insure a sealed fit
between the valve and valve inserts. Install the valves and valve springs into the
cylinder head. Install the cylinder head, pushrods and pushrod housing onto the
engine. Install new head gaskets and packings. Install the breather line to air
cleaner and cylinder head. Install the manifold-muffler. Install the intake manifold.
Install the carburetor and throttle controls as follows:
Adjust carburetor as follows:
a. With engine stopped turn main adjustment needle and idle adjustment needle fully clockwise to close.
b. Turn main adjustment needle three-quarters of a turn counterclockwise, and idle adjustment needle
one-half turn counter. clockwise. Start engine and run until warm.
misfires or seems low in power, open main exhaust needle. Adjust main adjustment needle until
engine delivers maximum power with minimum of exhaust smoke.
d. If engine application has a throttled speed adjustment, regulate idle mixture in a similar manner.
e. Regulate engine idle RPM by turning idle speed regulating screw clockwise or counterclockwise.
Adjust the governor as follows:
a. Remove the front throttle housing cover and gasket.
b. Open clevis and disconnect it from the throttle lever.
c. Hold the throttle 1/16 inch from the open position.
d. Loosen the locknut below the clevis and screw the clevis up or down until the clevis pin aligns with the
hole in the throttle lever.
e. Connect the clevis to the throttle lever and tighten locknut.
f. Install the gasket and front throttle housing cover.
g. To regulate engine speed, turn nut on control rod assembly clockwise to increase or counterclockwise
to decrease engine speed.
5-5
