ELECTRICAL
673831-Rev A 4-81
4
Starter Armature Inspection
Figure 4-74: Starter Armature Inspection
1. Check the contact area of the commutator (1) for
wear. Grind the commutator with emery paper if it is
slightly worn.
2. Measure the commutator diameter (2) with a
micrometer at several points.
Is the diameter less than 1.14 in. (29 mm)?
YES Commutator has too much wear. Replace
the armature.
NO Continue with next question.
Is the differences between diameter
measurements greater than 0.002 in. (0.05 mm)?
YES The commutator is out of round. Try to
correct the commutator on a lathe or replace
the armature. Repeat step 2.
NO Continue with step 3.
3. Measure the mica undercut (3).
Is the mica undercut less than 0.0079 in. (0.02
mm)?
YES Correct the mica undercut with a saw blade
and chamfer the segment edges. The saw
blade must be kept parallel with the armature
shaft.
NO Continue with step 4.
4. Check for continuity across the commutator
segments (4) and the armature coil core (5).
Is continuity indicated?
YES The armature is bad. Replace the armature.
NO Continue with step 5.
5. Check for continuity across the segments of the
commutator (4).
Is continuity indicated?
YES The armature is good.
NO The armature is bad, Replace the armature.
Starter Clutch Inspection
1. Check the pinion and if worn or damage, replace the
clutch assembly.
2. Check that the pinion turns freely and smoothly in the
overrunning direction and does not slip in the
cranking direction. If the pinion slips or does not turn
in both directions, replace the overrunning clutch
assembly.
Do not wash off the grease in the overrunning clutch with
chemicals or oils.
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