Section VI. FUEL SYSTEM - TM-10-4320-202-150039

TM 10-4320-202-15

3-19. Engine Backfire

31 5. Engine Overheats

Probable cause

Possible remedy

Probable cause

Report to direct support

Improper servicing of

Drain, clean and reservice

Intake valve not seating

with correct commodity.

properly.

maintenance.

engine fuel tank or

Remove, clean, and replace

Hot spot in combustion

crankcase.

Exhaust restricted _ _ _ _ _ _ _ _ Clean or replace muffler

chamber ignites fuel-air

cylinder head (para 341)

(para 3-38).

mixture when intake

valve is open.

Ignition improperly timed _ _Time magneto (para 3-31),

3-16. Engine Lacks Power

Possible remedy

Probable cause

3-20. Pump Fails to Deliver Fluid

Time magneto (para 3-31).

Ignition incorrectly

timed.

Possible remedy

Probable cause

Pump body empty _ _ _ _ _ _ Fill pump body.

Report to direct support

Valves not seating prop-

Low engine speed _ _ _ _ _ _ Increase engine speed.

maintenance.

erly.

Suction hose obstructed _ _ _ Remove, clean and replace

Worn piston rings _ _ _ _ _ _ _ _ Report to direct support

suction hose.

maintenance.

Drain, clean and reservice

Impeller clogged _ _ _ _ _ _ _ Remove pump housing and

Crankcase or fuel tank

with correct fuel or

free impeller (para 3-47).

improperly serviced.

Air leak in suction hose _ _ _ _ Repair leak.

lubricant.

Suction lift excessive _ _ _ _ _ Relocate pump to correct

excessive lift condition.

3-17. Engine Noisy

Probable cause

Possible remedy

3-21. Pump Fails to Deliver Rated Capacity

LOW grade of gasoline _ _ _ _ _ _ _ Drain, clean and reservice

fuel system with correct

Probable cause

Possible remedy

Tighten connection or re-

gasoline.

Air leak at suction hose

connection.

place hose assembly.

Engine operating at low

Increase engine speed.

Speed too low _ _ _ _ _ _ _ _ _ Increase engine speed.

speeds under heavy load.

Suction lift axcessive _ _ _ _ _ _ Relocate pump to correct

Hot spots in combustion

Remove, clean and replace

excessive lift condition.

chamber.

cylinder head (para

Clogged impeller _ _ _ _ _ _ Remove pump housing

341).

and free impeller (para

Ignition incorrectly timed _ _ _ Time magneto (para 3-31).

3-47) .

Worn or defective connect Report to direct support

ing rod bearings.

maintenance.

3-22. Pump Fails to Deliver Rated Pressure

Crankcase improperly

Drain and reservice with

serviced.

correct lubricant.

Probable cause

Possible remedy

Engine speed too low _ _ _ _ _ _ _ _ Increase engine speed

31 8. Engine Exhaust Smoke Excessive

3-23. Pump Works Temporarily, Then Stops

Possible remedy

Probable cause

Piston rings not seating

Report to direct support

Probable cause

Possible remedy

Leak in suction hose _ _ _ _ _ Repair leak or replace

properly.

maintenance.

hose.

Clogged crankcase

Remove, clean and replace

breather.

crankcase breather.

324. Pump Leaks at Mechanical Seal

Chock improperly set _ _ _ _ _ _ _ _ Adjust chock to full open.

Incorrect fuel-air mixture _ _ Adjust carburetor (para

Probable cause

Possible remedy

Seal worn or damaged _ _ _ _ _ _ Replace seal (para 3-47).

3-28).

Section VI. FUEL SYSTEM

fuel tank, carburetor, and speed control and

3 - 2 5 . General

governor linkage.

The fuel system includes those components

which provide the fuel-air mixture to the cylin-

3-26. Air Cleaner

der for combustion. The system includes the

a. Removal. Remove air cleaner (fig. 35).

air cleaner, fuel strainer, fuel lines and fittings,

3-9