C3, TM 9-2320-211-20
Troubleshooting---Vehicle
Item
Probable Cause
Corrective Action
Malfunction
No.
GASOLINE ENGINE
Check electrolyte specific gravity.
Engine will not crank.
a. Defective batteries, wiring con-
1
Replace defective batteries (para 2-22).
nections, or starting system.
Replace starter or solenoid (para 2-
Fill tanks.
a. Fuel tanks empty.
Engine cranks but fails to start.
2
Push choke in, open throttle and
b. Engine flooded.
crank engine to remove excessive
fuel.
Recharge batteries.
c. Insufficient cranking speed.
Refer to para 2-119.
d. No spark.
Inspect choke valve for proper
e. Carburetor choke inoperative.
operation and adjust choke controls
Clean lines and / or filters.
f. Clogged fuel tank ventline, fuel
line, or fuel filters.
Test pump; replace if defective (para
g. Fuel pump inoperative.
Refer to para 2-32.
a, Faulty ignition system.
Engine does not attain maxi-
3
Drain crankcase and refill to correct
b. Insufficient or improper grade of
mum revolutions per minute.
level with proper grade of oil (LO 9-
oil.
2320-211-12).
Refer to item below.
c. Engine overheats.
Check valve clearance and if
d. Improper valve adjustment.
necessary, adjust (para 2-45).
Remove cylinder head cover (para 2-
e. Sticking valves.
45), and apply penetrating oil to
valve stems. If valves still are not
free, notify supporting maintenance
personnel.
Test compression (para 2-43).
f. Faulty compression.
Clean or replace muffler (para 2-101)
g. Increased back pressure due to
or tailpipe (para 2-100).
clogged or collapsed muffler or
tailpipe.
Clean filters (para 2-73).
h. Clogged fuel filters.
Refer to item 2g.
i. Faulty fuel pump.
Check linkage and adjust as
j. Accelerator linkage improperly
necessary (para 2-67).
adjusted.
Remove and service air cleaners
k. Clogged air cleaners.
Adjust timing (para 2-120).
l. Distributor out of time.
Adjust idle setting and throttle
Engine misfires at idle speed.
a. Carburetor idle setting incorrect.
4
linkage (para 2-65 and 2-68).
Adjust choke control and linkage
b. Choke improperly positioned.
Adjust spark plug gap (para 2-121).
c. Spark plug gaps improperly set.
Refer to Table 2-4: IGNITION
d. Faulty distributor operation.
SYSTEM.
Use engine oil to check for leaks at
e. Vacuum leak.
throttle shaft, carburetor flange
and inlet manifolds.
Adjust valve clearance (para 2-45).
f. Improper valve clearance.
Notify supporting maintenance
g. Leaky cylinder head gasket.
personnel.
Check engine vacuum (para 2-44).
h. Defective or sticky valves.
Erratic vacuum gage readings at
constant engine speed, indicate
defective valve operation. Notify
supporting maintenance personnel
if gage reading is erratic.
`Refer to footnote at end of table.
