TM 3-4230-218-30&P
2-3.
TROUBLESHOOTING TABLE - Continued.
Table 2-1.
Direct Support Troubleshooting - Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
5.
ENGINE KNOCKS OR BACKFIRES - Continued.
Step 2.
Check ignition timing.
If engine ignition timing is off, time engine (refer to page 2-31).
If engine is in time, proceed to step 3.
Step 3.
Check for leaking or defective carburetor.
Replace or repair carburetor if defective (refer to page 2-40).
If carburetor is functioning properly, replace engine (see page
2-22).
Step 4.
a.
b.
c.
Step 5.
a.
b.
Check for carbon build-up in engine exhaust port.
Remove muffler (refer to page 2-22).
Remove carbon build-up from engine exhaust port using a wood
or plastic scraper.
Install muffler (refer to page 2-24).
Check for worn piston, cylinder, and connecting rod bearings.
Slowly rotate engine.
If engine makes a clanking or grating
noise or does not rotate smoothly, engine bearing, cylinder or
piston may be worn.
If engine bearing is worn, replace engine (refer to page 2-22).
If piston or cylinder is worn, replace worn components (refer
to page 2-35).
6.
ENGINE OVERHEATS.
See MALFUNCTION 5 if this condition exists.
7.
ENGINE RUNS, BURNER WILL NOT LIGHT.
See MALFUNCTION 4 if this condition exists.
2-6
