Starting motor running but too slow (small torque)

Possible symptoms of starting system trouble are as follows:

•Starting motor does not run (or runs slowly).
•Starting motor runs but fails to crank engine.
•Abnormal noise is heard.
•Starting motor does not stop running.

Proper diagnosis must be made to determine in which of the battery, wiring harness, starting motor (including magnetic switch) and engine the cause of each trouble lies.

Before removing the starting motor, check the following items to identify most possible causes of trouble.

1)Condition of trouble

2)Tightness of battery terminals (including ground cable connection on engine) and starting motor terminals

3)Discharge of battery

4)Mounting of starting motor

Condition	Possible Cause	Action
Starting motor running but too slow (small torque)	Faulty magnetic switch	Check magnetic switch.
	Low battery voltage	Check battery.
	Impossible charging due to deteriorated battery	Replace battery.
	Poor battery terminal connection	Check terminal connection or replace battery.
	Short circuit between commutator and armature	Check commutator.
	Burnt commutator	Check commutator.
	Defective brushes and/or brush springs	Check brushes and brush springs.
	Defective brush holder	Check brush holder.
	Defective starter end frame bushing	Check starter end frame bushing.