ENGINE PINGS OR KNOCKS UNDER LOAD.

TM 10-3930-633-12

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

3. ENGINE PINGS OR KNOCKS UNDER LOAD.

Step 1. Check for proper ignition timing.

Adjust timing to specifications.

Step 2. Check operation advance mechanism.

Replace distributor if advance mechanism malfunctions.

ENGINE

1. ENGINE WILL NOT START.

Step 1. Perform checks under "FUEL SYSTEM."

Step 2. Perform checks under "IGNITION SYSTEM."

Step 3. Check for low compression.

Refer to direct support maintenance.

2. ENGINE BACKFIRES, MISSES, OR OPERATES ERRATICALLY.

Step 1. Check malfunctions under (`IGNI TION SYSTEM."

Step 2. Check for intake manifold leak and partial loss of engine vacuum.

Tighten intake manifold bolts, or replace intake manifold.

Step 3. Check for blown head gasket (compression check).

Replace head gasket (para 4-72).

Step 4. Check for sticking valve (vacuum or compression check).

Refer to direct support maintenance.

Step 5. Check for excessive carbon build-up in cylinder head.

Replace cylinder head (para 4-72).

3. ENGINE STALLS OR VERY ROUGH AT IDLE.

Step 1. Check malfunctions under "IGNITION SYSTEM."

Step 2. Check malfunctions under "FUEL SYSTEM."

Step 3. Run a compression check for sticking valve or blown head gasket.

Replace cylinder head and gasket (para 4-72).

Step 4. Check for intake manifold leaks.

Tighten intake manifold bolts; replace gasket; replace cylinder head (para 4-72).

4. ENGINE LACKS POWER.

Step 1. Check malfunctions under "FUEL SYSTEM."

Step 2. Check malfunctions under "IGNITION SYSTEM."

Step 3. Run a compression check to locate sticking valve, worn rings, or blown head gasket.

Replace cylinder head and gasket; refer worn rings to direct support or general

support maintenance.

Step 4. Check for bent or obstructed muffler or tailpipe.

Repair or replace exhaust pipe or muffler (para 4-62).

5. HIGH OIL CONSUMPTION.

Step 1. Check for oil leaks at pan, gasket surfaces or crankshaft main seals.

Replace pan gaskets. Refer leaking seals to direct or general support maintenance.

Step 2. Check for improper grade and type of oil.

Drain and refill with proper grade and type of oil (LO 10-3930-633-12).

Step 3. Check for engine overheating; causing thinning of oil.

Refer to "COOLING SYSTEM" for causes of overheating.

Step 4. Perform compression check to determine if rings and valve guides are excessively worn.

Refer worn engine to direct or general support maintenance.

6. LOW OR NO OIL PRESSURE.

Step 1. Check oil level.

Fill crankcase with proper quantity and type of oil (LO 10-3930-633-12).

Step 2. Check for oil leakage at cylinder head, crankshaft main seals, or timing chain cover.

Refer to direct or general support maintenance.

TRANSMISSION

1. TRANSMISSION WILL NOT ENGAGE.

Step 1. Check fluid level.

Refill with proper fluid (LO 10-3930-633-12).

Step 2. Check to see if control cable has become disconnected.

Reconnect control cable at selector or transmission.

2. TRANSMISSION OPERATES ERRATICALLY.

Step 1. Check for low fluid level.

Refill with proper fluid (LO 10-3930-633-12).

Step 2. Check for fluid foaming due to overfilling.

Drain level back to FULL mark on dipstick.

3. TRANSMISSION FLUID OVERHEATS.

Step 1. Check for dragging parking brake or service brake.

Adjust brakes to eliminate drag (para. 4-79).

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