TM 5-4310-335-14
Table 4-2. TROUBLESHOOTING (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
b.
Clean with an approved cleaning solvent and dry thoroughly. Inspect body for cracks, breaks,
evidence of leakage and stripped or damaged threads. Inspect plunger arm for cracks, breaks,
distortion and excessive wear. Inspect spring for cracks, breaks, or distortion. Test fuel pump for
proper operation by holding fuel pump and work plunger arm up and down. By holding a finger
lightly over the Inlet side of the pump, you should feel a suction. Test pump outlet side of the
pump. The pressure reading should be 3.q to 4.5 psi. Inspect fuel lines and fittings for cracks,
breaks, evidence of leakage, abnormal bends, dents and stripped threads. Replace a damaged or
defective pump.
Step 4. Check the carburetor and throttle controls for adjustment. If the adjustment of the carburetor and throttle
controls does not resolve the problem, replace the carburetor and/or throttle controls.
Remove the carburetor and throttle controls.
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 (38 )
F
C
- 138 (59 ).
F
C
a.
Clean the carburetor and throttle controls with an approved cleaning solvent and dry with filtered
compressed air. Wipe thoroughly with clean, dry cloth if air is not available.
b.
Inspect for defects, cracks, and damage. Replace controls or carburetor if defective or damaged.
c.
Reassemble In reverse of removal procedure. Use new gaskets throughout Tighten all nuts, bolts,
and screws securely.
3.
ENGINE MISSES OR RUNS ERRATICALLY
Step 1. Remove the spark plug cable from the spark plug. Hold the spring located at the spark plug end of the
cable approximately 1/ inch from the spark plug or any part of the engine. Turn the engine over using the
starting rope. If a spark jumps from spring to engine, then remove spark plug, reconnect cable and ground
spark plug to the side of the engine. Turn engine over and see if there is a spark at the electrode end of the
plug. If there is a good strong spark at the spark plug then go on to Step 2. But if no spark Is seen at the
spark plug or cable, then the contact assembly, condenser, and engine timing should be checked.
If spark plug cable requires replacement, loosen connector nut on each end of cable, remove
and replaceable. If spark plug needs replacing, remove spark plug. Before installation of new
spark plug measure the electrode gap with a wire, or leaf thickness gage. A slight drag
should be felt when monitoring the correct measurement. The desired clearance is 0.028 to
0.033 inch. Adjust the gap by bending the outside electrode until the gap Is properly set.
Step 2. Check fuel filter to see if It is clogged or filter element Is dirty. Remove outlet line from the filter to check
flow of fuel. If no fuel or a very small flow of fuel is noticed at the outlet side of the filter, remove and clean
the fuel filter. If fuel flow Is sufficient, go on to Step 3.
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 (38 )
F
C
- 138 (59 ).
F
C
To remove and clean the fuel filter, shut off fuel at top of filter then loosen thumbscrew
holding bowl to the filter, swing the bail to one side and remove the bowl. Remove and clean
the filter in an approved cleaning solvent. Inspect the gasket and replace if necessary.
Step 3. Check the service indicator first. If it shows in the red, then remove air cleaner element. If
engine starts, air cleaner needs servicing.
Service the air cleaner as follows:
a. Loosen the two retaining bolts connecting air cleaner body to the cover.
b. Remove cover and element from body.
c. Blow out with compressed air, from clean side to dirty side of element. If compressed air is not
available, wash with a detergent and water.
d. Wipe inside of cover and body.
NOTE
Do not wash element in a cleaning solvent
e. Reinstall element and tighten retaining bolts.
4.
ENGINE OVERHEATS
Step 1. Check engine air circulation.
Clean cylinder head, cylinder and oil pan fins with a wire brush. Clean duets, covers and deflectors
with compressed air.
4-6
