Field Coil Tests; Loose Electrical Connections; Turning The Commutator - MerCruiser GM4 Service Manual

2. If meter hand moves, armature is grounded and
must be replaced.
c
a
a - Commutator
b - Armature Core
c - Shaft
d - Growler

Field Coil Tests

TEST FOR OPEN CIRCUIT
1. With continuity meter, place one lead on each end
of field coils (insulated brush and field connector
bar).
2. If meter does not move, field coils are open and
must be replaced.
Index
90-816462 2-695
TEST FOR GROUND
IMPORTANT: Be sure that positive brushes and
leads do not contact field frame assembly during
test, or false reading will result.
b c
1. With continuity meter, place one lead on field con-
d
01441
2. If meter hand moves, field coils are grounded and

Loose Electrical Connections

If open soldered connection of armature to commuta-
tor leads is found during inspection, resolder with res-
in flux.
IMPORTANT: Never use acid flux on electrical
connections.

Turning the Commutator

When inspection shows commutator roughness,
clean as follows:
1. Turn down commutator in a lathe until thoroughly
2. Recheck armature for shorts as outlined.
72635
nector bar and other lead on grounded brush.
must be replaced.
cleaned.
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STARTING SYSTEM - 4A - 15