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ELECTRIC STARTER
5-51
EAS24790
CHECKING THE STARTER MOTOR
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 that has been grounded to fit the
commutator.
TIP
The mica of the commutator must be undercut
to ensure proper operation of the commutator.
4. Measure:
• Armature assembly resistances (commu-
tator and insulation)
Out of specification → Replace the
starter motor.
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a. Measure the armature assembly resis-
tances with the pocket tester.
b. If any resistance is out of specification,
replace the starter motor.
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5. Measure:
• Brush length “a”
Out of specification → Replace the
brushes as a set.
6. Measure:
• Brush spring force
Out of specification → Replace the brush
springs as a set.
Commutator wear limit
21 mm (0.83 in)
Mica undercut
1.5 mm (0.06 in)
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Armature coil
Commutator resistance “1”
0.013–0.015 Ω at 20 °C (68 °F)
Insulation resistance “2”
Above 1 MΩ at 20 °C (68 °F)
Brush length wear limit
3.5 mm (0.14 in)
Brush spring force
5.52–8.28 N (563–844 gf,
19.87–29.80 ozf)