TM10-3930-660-20 Table  2-3. Mechanical Troubleshooting (Cont’d) TEST OR INSPECTION CORRECTIVE ACTION Step 3. Check Check Step 4. Check Refer 18. ENGINE WILL Step 1. Check for poor quality fuel. that quality no. 2 fuel is being used. for exhaust restriction or inadequate intake air. to Test 10, Excessive Exhaust Smoke in this table (Table 2-3). NOT SHUT  OFF for inoperative fuel shutoff solenoid. Stop the engine mechanically with manual fuel Test fuel shutoff valve, para. 5-3. shutoff valve lever. Step 2. Check for engine running on fumes drawn into the air intake. Check the air intake ducts for the source of the fumes. 19. EXCESSIVE VIBRATION Step 1.  Check for engine not running smoothly. Refer to Test 7. Engine Runs Rouqh or Misfiring, in this table (Table 2-3). Step 2. Check for loose Check for loose 216 in. lb. or damaged fan. fan mounting screws and, if necessary, tighten to 20. EXCESSIVE ENGINE NOISES Step 1. Check for drive belt squeal caused by insufficient belt tension or abnormally high loading. Replace belt if necessary, para. 7-9. 2-36