4841 Starter motor

Visual Inspection


Check for any sign of
- Overheating
- Burning
- Physical damage of insulation and coil winding
- Poling

Ground Circuit Tests

Test the ground by setting to ohm on your meter and poke the probebetween each of the commutator segments and the armature core or shaft. 

Continuity Circuit Test

With the Ohm meter in the same range check continuity between one of the commutator segments while moving the second probe around on each of the other commutator segments. 

Testing Commutator

Measure the Commutator diameter with a vernier caliper and check the mica undercut depth as necessary. 

Testing for internal short circuits using a growler

Alternative Method of Testing Armature
Using a 48volt test light

Continuity test

Keep one probe on one segment and move the other probe around each of other segments.The test light should glow.

Ground test

Place one probe on a commutator segment and the other on either the armature core or shaft. The test light should not glow.

Test the Field coils for Continuity
Checking for continuity in the field winding place the ohm meter probes on each end of the field winding. Result 0.01ohm


Test the Field coils for grounding
Ohm meter place the positive probe on the field wire or brush, then the common probe on the body of the starter. The meter should read Infinity.
Brushes


Brush Holder Assembly
Check for short circuit between insulated brushes and holder set the Ohms meter on the lowest resistance.  Place one of the probes on the brush and the other on the metal retaining plate