Motor running but too fast

Motor not running no operating sound of magentic switch

Starter motor running too slow

Starter motor running but not cranking

Burnt commutator

Battery discharged

Worn brushes

Worn pinion tip

Provide grip over armature shaft

Avoid the side way movement of armature shaft

Prevent pinion striking fly wheel

Resist wear on the fly wheel

Faulty regulator

Loose mountings

Wornout bearing

Loose drive pully

Open rectifier circuit

Open field current

Voltage regulator setting too low

Voltage regulator setting too high