Evinrude 4906B 4HP 1969 Owner's Manual page 219

6-30 ELECTRICAL
ARMATURE TESTING
Testing for a Short
3- Position the armature
then hold a hacksaw blade over the arma-
ture core. Turn the growler switch to the
position. Slowly rotate the armature.
ON
the hacksaw blade vibrates, the armature or
commutator has a short.
between the commutator
ture. Perform the test again.
saw blade still vibrates during the test, the
armature has a short and MUST be replaced.
TEST LEADS
on a growler,
If
Clean the grooves
bars on the arma-
If the hack-
Testing for a Ground
4- Obtain a test lamp or continuity me-
ter. Make contact with one probe lead on
the armature core and the other probe lead
on the commutator
or the meter indicates continuity, the arma-
ture is grounded and MUST be replaced.
Checking the Commutator
5- Check between
as shown in the accompanying
The test light should light, or the meter
should indicate continuity.
tor fails the test, the armature
replaced.
Turning the Commutator
6- True the commutator,
a lathe. NEVER undercut the mica because
the brushes are harder than the insulation.
Undercut the insulation
mutator bars 1/32" to the full width of the
insulation and flat at the bottom.
ular groove is not satisfactory.
under-cutting work is completed,
the slots carefully to remove dirt and cop-
per dust. Sand the commutator
No. 00 sandpaper to remove any burrs left
from the undercutting.
a second time on the growler for possible
short circuits.
CORRECT
bar. If the lamp lights,
Bar
or check bar-to-bar
illustration.
If the commuta-
MUST be
if necessary, in
between the com-
A triang-
After the
clean out
lightly with
Check the armature
INCORRECT