BOMBARDIER Johnson 90 Service Manual page 128

ELECTRICAL
STARTER MOTOR
INSPECTION and SERVICING
Armature and Commutator
1. lnspect commutator surface for gum or dirt. Clean with
#500 grit emery paper
®
if necessary.
2. Measure commutator outside diameter.
1@1
Vernier calipers
Commutator outside diameter:
Standard: 29.0 mm (1.14 in)
Service limit: 28.0 mm (1.10 in)
lf measurement exceeds service limit, replace armature.
3. Measure commutator undercut (depth) between mica
(insulator) and segments.
Commutator undercut
CD
(depth):
Standard: 0.5 - 0.8 mm (0.02 - 0.03 in)
Service limit: 0.2 mm (0.01 in)
lf measurement exceeds service limit, cut mica to specified
depth.
NOTE:
Remove ali particles of mica and metal using compressed
air.
. 1 ,WARNING
Wear safety glasses when using compressed air.
SEGMENT
(D
undercut
4-16