2B-16 - ELECTRICAL and IGNITION 90-817643R1 DECEMBER 1996
4. Remove components from armature.
11658
a
b
c
d
e
f
a - Spacer
b - Spring
c - Drive Assembly
d - Drive End Cap
e - Armature Shaft
f - Washer
Cleaning and Inspection
1. Clean all motor parts.
2. Check pinion teeth for chips, cracks or excessive wear.
3. Replace the drive clutch spring and/or collar, if tension
is not adequate, or if wear is excessive.
4. Check that the brush holder is not damaged or is not
holding the brushes against the commutator.
5. Replace brushes that are pitted or worn to less than
1/4” (6.4mm) in length. Refer to “Brush Replacement”,
following.
6. Replace a damaged or excessively worn bushing in
the end cap.
7. Check the armature conductor (commutator bar junc-
tion) for a firm connection. A poor connection usually
results in a burned commutator bar.
8. Re-surface and undercut a rough commutator, as fol-
lows:
!
CAUTION
Do not turn down the commutator excessively.
a. Re-surface the commutator and undercut the in-
sulation between the commutator bars 1/32″
(0.8mm) to the full width of the insulation, make
sure that the undercut is flat.
b. Clean the commutator slots after undercutting.
c. De-burr the commutator lightly with No. 00 sand-
paper, then clean the commutator.
d. Check the armature on a growler for shorts. See
“Testing”, following.
9. Open-circuited armatures often can be saved where
and open circuit is obvious and repairable. The most
likely place for an open circuit is at the commutator
bars. Long cranking periods overheat the starter motor
so that solder in the connections melts. The poor con-
nections cause arcing and burning of the commutator
bars.
10. Repair bars, that are not too badly burned, by re-sold-
ering the leads in bars (using rosin flux solder) and
turning down the commutator in a lathe to remove
burned material, then undercut the mica.
11. Clean out the copper or brush dust from slots between
the commutator bars.
12. Check the armature for shorts and ground. See “Test-
ing”.
Testing
ARMATURE TEST FOR SHORTS
Check armature for short circuits by placing on growler and
holding hack saw blade over armature core while armature
is rotated. If saw blade vibrates, armature is shorted. Re-
check after cleaning between commutator bars. If saw
blade still vibrates, replace armature.
11669
To Next Page
Loading...
