Engine Misses or Runs Erratically - TM-5-4320-240-150038

3-18. Oil Pressure Low

Probable Cause

Possible Remedy

Carburetor out of adjusts........ Adjust carburetor (par.

Probable Cause

Possible Remedy

Caution: If the engine oil pressure gage does

ment.

8-83).

not show a minimum of 7 psi at idle speed a few

Spark plugs defective............. Clean and gap or replace

seconds after starting, stop the engine and check

spark plugs (para 8-47).

for cause.

No fuel ................................ ...Add fuel to tank.

Not enough oil in engine......... Fill to prescribed level.

3-15. Engine Misses or Runs Erratically

Engine oil pressure

Replace gage (para 3-66).

Probable Cause

Possible Remedy

gage faulty,

Plugged air cleaner ............... Service air cleaner (para

Incorrect oil viscosity .............. Drain oil and replace with

8-88).

correct oil.

Governor sticking .................. Clean linkage.

3-19. Engine Overheats

Spark plugs defective............. Clean and gap or replace

Probable Cause

Possible Remedy

spark plugs (para 8-47).

Thermostat defective ............. Replace thermostat (para

Magneto defective.................. Adjust

replace

3-51).

magneto (para 8-46).

Radiator defective.................. Clean radiator (para 3-

52).

3-16. Engine Noise

Water pump defective............ Replace

water

pump

Probable Cause

Possible Remedy

Engine mounting bolts Tighten mounting bolts, loose.

(para 3-50).

Insufficient oil Add oil.

3-20. Engine Lacks Power

3-17. Engine Stops Suddenly

Probable Cause

Possible Remedy

Governor defective ................ Adjust

replace

Probable Cause

Possible Remedy

No fuel in tank ....................... Fill fuel tank,

governor (para 8-34).

Ignition wiring faulty ............... Check wire from switch to

Magneto defective.................. Adjust

replace

magneto for a possible

magneto (para 3-46).

ground.

Magneto failure ..................... Replace magneto (para 8-

3-21. Generator Fails to Function

46).

Probable Cause

Possible Remedy

Oil pressure safety

Check oil level; replenish

Generator-regulator................ Replace defective regula-

switch trips.

supply if necessary, Re-

defective.

tor (para 3-44).

set oil pressure switch.

Start engine and check

3-22. Pump Falls to Prime

for oil pressure. If pres-

Probable Cause

Possible Remedy

Air leak in suction line ............ Tighten hose connections.

sure is adequate but

Check for pinholes in

switch shuts off engine,

hose.

Check for

replace engine oil pres-

collapsed lining.

sure gage and integral

Suction strainer or

Clear line or strainer.

safety switch (para 8-

suction line plugged.

66).

Chamber not completely

Fill chamber.

Water temperature

Check radiator water

filled for priming,

safety switch trips.

level; replenish supply if

necessary. Reset water

temperature

switch.

3-23. Noisy Pump Operation

Start engine and check

Probable Cause

Possible Remedy

Excessively high suction

Move pump closer to sup-

for water temperature,

lift causing cavitation.

ply.

If temperature is below

safe operating level but

3-24. Pump Fails to Deliver Rated Capacity

switch shuts off engine,

Probable Cause

Possible Remedy

replace engine water

Engine lacks speed................ Check governor adjust-

temperature gage and

ment (para 3-34).

safety switch. (para 8-

67).

3-9