Inspect commutator for dirt or burn spots. Correct with sandpaper or lathe as necessary.
To check armature for a grounded circuit, use ohmmeter to check for continuity between commutator and armature coil core. See Fig 1 . No continuity should exist. Replace armature if continuity exists.
To check for an open circuit, use ohmmeter to check for continuity between individual brush segment at commutator end of armature. See Fig 1 . Continuity should exist between each individual brush segment. Replace armature if no continuity exists on any brush segment.
Support armature in "V" blocks, with "V" block positioned at each bearing end of armature. Using dial indicator, check armature runout at commutator end of armature. Replace armature if armature runout exceeds .015" (.40 mm).
Using caliper, measure commutator outside diameter at center of commutator. Replace armature if commutator outside diameter is not within specification. See STARTER SPECIFICATIONS .
Measure insulator depth at grooves between commutator segments. See Fig 2 . Replace armature if insulator depth is not within specification. See STARTER SPECIFICATIONS .

Fig 1: Testing Armature For Grounded & Open Circuits

Courtesy of SUZUKI OF AMERICA CORP.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Bench Testing: Armature