Table of Contents
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ELEC
STARTER MOTOR
ARMATURE
1. Inspect the commutator surfaces and if
these are dirty or burnt, clean with 400-
grit wet-or-dry sandpaper.
2. Inspect the commutator deflection with
a dial gauge and block and replace the
armature if the deflection is out of spec-
ification.
Maximum deflection:
0.05 mm (0.0020 in)
If the deflection is greater than the spec-
ified deflection, replace the armature.
3. Measure the diameter of the commuta-
tor.
Standard diameter:
50, 60, 70 hp: 30 mm (1.18 in)
75, 80, 90 hp: 33 mm (1.30 in)
Minimum diameter:
50, 60, 70 hp: 29 mm (1.14 in)
75, 80, 90 hp: 31 mm (1.12 in)
If the commutator diameter is out of
specification, replace the armature.
4. Measure the commutator mica under-
cut depth.
Standard mica undercut depth:
0.8 mm (0.03 in)
Minimum undercut depth:
0.2 mm (0.01 in)
If the undercut depth is less than the
specified minimum, scrape between the
segments with a hacksaw blade, then
remove all particles of mica and metal
with compressed air.
8-33
E
Chapters
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