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ELEC
ELECTRIC STARTING SYSTEM
INSPECTION AND REPAIR
1. Check:
● Commutator
Dirt → Clean with 600 grit sandpaper.
2. Measure:
● Commutator diameter a
Out of specification → Replace the
starter motor.
3. Measure:
● Mica undercut a
Out of specification → Scrape the mica
to the proper measurement with a
hacksaw blade which has been
grounded to fit the commutator.
NOTE:
The mica must be undercut to ensure proper
operation of the commutator.
Min. commutator diameter
16.6 mm (0.65 in)
Mica undercut
1.5 mm (0.06 in)
4. Measure:
● Armature assembly resistances (com-
mutator and insulation)
Out of specification → Replace the
starter motor.
● Measure the armature assembly resis-
tances with the pocket tester.
Pocket tester
YU-03112-C/90890-03112
Armature assembly
Commutator resistance 1
0.0117 ~ 0.0143 Ω at 20 ˚C
(68 ˚F)
Insulation resistance 2
Above 1 MΩ at 20˚C (68 ˚F)
● If any resistance is out of specification,
replace the starter motor.
