Inspect commutator for dirt or burn spots. Correct with sandpaper or lathe as necessary.
Using DVOM, check for grounded circuit. Check for continuity between commutator and armature coil core. See Fig 1. Continuity should not be present between commutator and armature coil core. If continuity exists, replace armature.
Using DVOM, check for an open circuit. Check for continuity between each individual commutator segment at commutator end of armature. See Fig 1. Continuity should exist between each individual commutator segment. Replace armature if continuity does not exist between any 2 segments.
Support armature between "V" blocks. Using dial indicator, check armature runout at commutator end of armature. Normal armature runout should be less than .002" (.05 mm). Replace armature if armature runout exceeds .015" (.40 mm).
NOTE: Bent commutator/armature must be replaced.
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