TM 10-3930-653-14&P 4-1-2 TROUBLE DIAGNOSES AND CORRECTIONS Condition Probable cause Corrective action CANNOT CRANK Improper grade oil Replace with proper grade oil. ENGINE OR SLOW Discharged battery. Charge battery. CRANKING Faulty battery. Replace Loose fan belt Adjust Trouble in charge system. Inspect. Wiring connection trouble in starting circuit. Correct. Faulty starter switch. Repair or replace. Faulty starter motor. Repair or replace (Trouble-shooting procedure on starting circuit) Switch on the starting motor with light "ON" When light goes off or dims considerably. a.  Check battery b.  Check connection and cable. c.  Check starter motor When light stays bright. a.  Check wiring connection between battery and starter motor b.  Check starter switch. c.  Check starter motor. ENGINE WILL CRANK NORMALLY BUT WILL NOT START In this case, the following may exist, but in many cases ignition system or fuel system could be defective. Ignition system trouble Fuel system trouble Valve mechanism does not work properly Low compression (Trouble-shooting procedure) Check spark plug first by following procedure. Disconnect high tension cable from one spark plug and hold it about 10 mm (0.4 in) from the engine metal part and crank the engine. If good spark occurs. a.  Check spark plug. b.  Check ignition timing. c.  Check fuel system. d.  Check cylinder compression If no spark occurs Check the current flow in primary circuit. Very high current. Inspect for shorted primary circuit. Check breaker point operation. 4-2