Starter No Load Test - Evaluation

Low tree speed and high current draw indicates the following conditions:
^ Too much friction
The following conditions may cause too much friction:
- Tight bushings
- Worn bushings
- Dirty bushings
- A bend in the armature that allows the armature to drag.
^ Shorted armature
Inspect for a shorted armature on a growler after disassembly.
^ Grounded armature or fields
Inspect further after disassembly.

Failure to operate and high current draw indicates the following conditions:
^ A direct ground in the terminal or fields
^ Frozen bearings

Failure to operate and low or no current draw indicates the following conditions:
^ Open solenoid windings
^ Open field circuit
Inspect the open field circuit after disassembly by inspecting internal connections.
^ Open armature coils
Inspect the commutator for badly burned bars after disassembly.
^ Broken brush springs
^ Worn brushes
^ High insulation between the commutator bars
^ Other conditions that may prevent good contact between the brushes and the commutator

Low no-load speed and low current draw indicates the following conditions:
^ High internal resistance due to poor connections
^ Defective leads
^ Dirty commutator
^ Open solenoid windings
^ Open field circuit
Inspect the condition of the internal components after disassembly in order to find an open field circuit.
^ Open armature coils
Inspect the commutator for badly burned bars after disassembly.
^ Broken brush springs
^ Worn brushes
^ High insulation between the commutator bars or other conditions which may prevent contact between the brushes and the commutator

High free speed and high current draw indicate shorted fields.
^ If you suspect shorted fields, replace the field coil assembly.
^ Use a growler in order to inspect for shorted armature.

Rated current draw and no-load speed indicate the normal condition of the starter motor assembly. If any of the above conditions are unsatisfactory, refer to Starter Motor Overhaul. Starter Motor Overhaul