Mariner 100, Service Manual, Page: 53 / 391

2B-22 90-13645--2 495 ELECTRICAL AND IGNITION
Starter Cleaning, Inspection and
Testing
CLEANING AND INSPECTION
1. Clean all starter motor parts.
2. Check pinion teeth for chips, cracks or excessive
wear.
3. Replace the drive clutch spring and/or collar if ten-
sion is not adequate or if wear is excessive.
4. Inspect brush holder for damage or for failure to
hold brushes against commutator.
5. Replace brushes that are pitted or worn to less
than 1/4
″
(6.4mm) in length.
6. Inspect the armature conductor (commutator bar
junction) for a tight connection. A loose connec-
tion (excessive heat from prolonged cranking
melts solder joints) results in a burned commuta-
tor bar.
7. Resurface and undercut a rough commutator as
follows:
Do not turn down the commutator excessively.
CAUTION
a. Resurface the commutator and undercut the in-
sulation between the commutator bars 1/32
″
(0.8mm) to the full width of the insulation and so
that the undercut is flat.
b. Clean the commutator slots after undercutting.
c. Sand the commutator lightly with No. 00 sand-
paper to remove burrs, then clean the commu-
tator.
d. Recheck the armature on a growler for shorts
as specified in the following procedure (“Test-
ing”).
8. Open-circuited armatures often can be repaired.
The most likely place for an open circuit is at the
commutator bars, as a result of long cranking peri-
ods. Long cranking periods overheat the starter
motor so that solder in the connections melts and
is thrown out. The resulting poor connections then
cause arcing and burning of the commutator bars.
9. Repair bars, that are not excessively burned, by
resoldering the leads in bars (using rosin flux sol-
der) and turning down the commutator in a lathe
to remove burned material, then undercut the
mica.
10. Clean out the copper or brush dust from slots be-
tween the commutator bars.
11. Check the armature for ground. See the following
procedure (“Testing”).
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. Recheck after cleaning between
commutator bars. If saw blade still vibrates, replace
armature.
11669
ARMATURE TEST FOR GROUND
1. Set ohmmeter to (R x 1 scale). Place one lead of
ohmmeter on armature core or shaft and other
lead on commutator.
2. If meter indicates continuity, armature is
grounded and must be replaced.
11675