TM 5-3810-289-12
Chart 4-1. Troubleshooting
Malfunction
Probable cause
Corrective action
a. Engine too cold.
a. Use starting aid.
1. Engine fails to start.
b. Check fuel tank.
b. Lack of fuel.
c. Clogged fuel filters.
c. Clean element in primary filter. Replace
elements in final filter (para 4-23).
a. Clogged fuel filter elements.
a. Clean element in primary filter. Replace
2.
Irregular firing of engine.
elements in final filter (para 4-23).
Engine overheating indicated. a. Loose fan belts.
a. Adjust fan belt (para 4-32).
3.
B Radiator clogging.
b. Clean radiator (para 4-31).
d. Thermostats defective.
d. Test thermostats (para 4-33).
e. Radiator sealed pressure overflow e. Clean or replace (para 4-31).defective.
a. Main bearings worn or burned
a. Replace main bearings (report to
4.
Engine knocks excessively.
out.
direct support maintenance).
burned out.
direct support maintenance).
5.
Low or no lubricating oil pres- Defective gage.
Replace gage (56, fig. 4-31). sure indication.
Low or no fuel pressure indica- a. Clogged fuel filters.
a. Clean element in primary filter.
6.
tion.
Replace elements in final filter (para 4-
23).
b. Defective gage.
Replace gage (56, fig. 4-31).'
Starter will not crank engine. a. Batteries weak.
a. Test batteries and charge if necessary
7.
b. Loose connection or defective
b. Inspect and replace damaged wir-
wiring.
ing. Inspect all connections to starter,
magnetic switch, ignition switch, and
batteries.
c. Defective switch.
c. Inspect all switches to determine their
condition. Connect jumper lead around
any switch suspected of being defective; if
system functions, replace the bypass
switch.
d. Commutator dirty or worn.
d. Inspect
commutator
by
removing
inspection plugs. If commutator is dirty or
slightly grooved, polish by placing a strip
of fine sandpaper around commutator and
under
brushes
(rough side toward
commutator) and rotate armature. Blow
dust from commutator after polishing.
e. Starter brushes worn.
e. Replace brushes.
a. Alternator drive belt loose or
a. Adjust or replace drive belt (para 4-36).
8.
Alternator not charging.
broken.
b. Alternator inoperative.
b. Refer to paragraph 4-35.
a. Alternator belt not properly ad-
a. Adjust belt (para 4-36).
9.
Alternator output low or un-
steady.
justed.
b. Brushes sticking in brush holder. b. Free brushes in holder.
4-2
