ELECTRIC STARTER
5-38
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.
NOTE:
The mica of the commutator must be undercut
to ensure proper operation of the commutator.
4. Measure:
• Armature assembly resistances (commuta-
tor and insulation)
Out of specification → Replace the starter
motor.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Measure the armature assembly resis-
tances with the pocket tester.
b. If any resistance is out of specification,
replace the starter motor.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
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.
Limit
27.0 mm (1.06 in)
Mica undercut (depth)
0.70 mm (0.03 in)
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Armature coil
Commutator resistance “1”
0.0012–0.0022 Ω at 20°C (68°F)
Insulation resistance “2”
Above 1 MΩ at 20°C (68°F)
Limit
3.50 mm (0.14 in)
Brush spring force
7.16–9.52 N (25.77–34.27 oz)
(730–971 gf)