Section III. TROUBLESHOOTING
engine and check for oil
38.
General
pressure. If pressure is
This section provides information useful in
adequate but switch shuts
diagnosing and correcting unsatisfactory operation or
off engine, replace engine
failure of the centrifugal pump and its components.
oil pressure gage - and
Each trouble symptom stated is followed by a list of
integral safety switch
probable causes of the trouble. The possible remedy
recommended is described opposite the probable cause.
Any trouble beyond the scope of organizational
43.
Oil Pressure Low
maintenance shall be reported to direct support
maintenance.
Probable cause
Possible remedy
Caution
39.
Engine Falls to Sart or Hard to Start
t
If the engine oil pressure gage
Probable cause
Possible remedy
does not show a minimum of 7 psi
Starter fails to crank
Check and repair electrical
at Idle speed a few seconds after
engine.
system and starting motor
staring, stop the engine and check
for cause
.
Carburetor out of
Adjust carburetor (para
Not enough oil in
Fill to prescribed level.
adjustment.
59a).
engine.
Valves defective................. epair or replace valves
R
Engine oil pressure gage Replace gage (para 90).
(para116).
faulty.
Spark plugs defective.........Clean and gap or replace
.
Oil pressure relief valve Remove relief valve; clean
spark plugs (para 71).
sticking open.
valve and hole in block.
Magneto defective.............. epair or replace magneto
.
R
Reassemble(para 81).
(para70 or 110).
Oil pump screen clogged...Clean oil pump screen
..
40.
Engine Misses or Runs Erratically
Probable cause
Possible remedy
Oil pump defective ............. epair or replace oil pump
.
R
Governor defective
Repair or replace governor
(para61 or 106).
Main or connecting rod
Replace main bearings
Valves burned, warped, Repair or replace valves or
bearings loose.
(para 121). Replace
broken.
(para116).
connecting rod bearings
Valve springs weak or
Replace valve springs (para
broken.
116).
44. Engine Overheats
Valve seats cracked........... eplace exhaust valve seat
.
R
inserts and reface intake
Probable cause
Possible remedy
Thermostat defective .........Replace thermostat (para
valve seats(para 116).
Spark plugs defective.........Clean and gap or replace
.
Radiator defective.............. lean radiator (para 76).
.
C
spark plugs (para 71).
W ater pump defective........Repair or replace water
.
Magneto defective.............. epair or replace magneto
.
R
(para70 or 110).
Cylinder head cracked
Replace cylinder head (para
41. Engine Noisy
Probable cause
Possible remedy,
Crankcase water jacket
Replace engine block (para
Engine mounting bolts
Tighten mounting bolts
cracked.
122).
loose.
(para102).
45. Exhaust Smoke Excessive
Flywheel loose or
Tighten or replace flywheel
defective.
(para120).
Probable cause
Possible remedy
Piston rings and/or
Replace piston rings and/or
Main or connecting rod
Replace bearings (para 119
pistons defective.
pistons (para 119).
bearings loose.
and121).
46. Engine Lacks Power
42. Engine Stops Suddenly
Probable cause
Possible remedy
Probable cause
Possible remedy
Governor defective............. epair or replace governor
R
No fuel in tank...................Fill fuel tank.
.
.
(pars 61 or 106).
Ignition wiring faulty ........... heck wire from switch to
.
C
Valves burned, warped,.....Repair or replace valves
..
mag- neto for a possible
or broken
ground.
Valve springs weak or
Replace valve spring (para
Magneto failure................... eplace or repair magneto
R
broken.
116).
(para 70 or 110).
Valve seats cracked
Replace exhaust valve seat
Probable cause
Possible remedy
inserts
and
reface
Oil pressure safety
Check oil level; replenish
intake
switch trips.
supply if necessar. Reset
y
valve seats (para 116).
oil pressure switch. Start
Magneto defective.............. epair or replace magneto
.
R
Piston rings and/or
Replace piston rings and/or
pistons defective.
pistons (para 119).
TAGO 6358-A
25