TM 10-3930-653-14&P 4-7-2.  TROUBLE DIAGNOSES AND CORRECTIONS 4-7-2-1. Starting motor Condition Probable cause Corrective action Starting motor will not Discharged battery. Charge or replace battery. operate. Faulty solenoid switch. Repair or replace solenoid switch. Loose terminal connections. Clean and tighten terminal. Worn brushes. Replace brushes. Faulty starting motor. Remove starting motor and test. Noisy starting motor. Loose securing bolt. Tighten bolt. Worn pinion gear. Replace pinion gear. Poor lubrication. Add oil. Worn commutator. Replace. Worn brushes. Replace brushes. Starting motor Discharged battery. Charge or replace battery. cranks slowly. Loose connection of terminal. Clean and tighten terminal. Worn brushes. Replace brushes. Locked brushes. Inspect brush spring tension or repair brush holder. Dirty worn commutator. Clean and repair. Armature rubs field coil. Replace assembly. Faulty solenoid switch. Repair or replace switch. Starting motor Worn pinion. Replace pinion. operates but does not Locked pinion guide. Repair pinion guide. crank engine. Worn ring gear. Replace ring gear. Starting motor will not Faulty solenoid switch. Repair or replace solenoid switch. disengage even Damaged gear teeth. Replace faulty gear. when ignition switch is turned off. 4-89