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ENGINE ELECTRICAL
6D-41
Wiring: Inspect the wiring for damage. Inspect all
connections to the cranking motor, solenoid, ignition switch,
and battery, including all ground connections. Clean and
tighten all connections as required.
Fig. 6D-47 Cross Section of Starting Motor
disassembly.
No-Load Test (Fig. 6D-48)
Solenoid and Ignition Switch: Inspect all switches
to determine their condition. Connect a jumper lead around
any switch suspected of being defective. If the system
functions properly using this method, repair or replace the
bypassed switch.
Motor: If the battery, wiring and switches are in
satisfactory condition, and the engine is known to be
functioning properly, remove the motor and follow the test
procedures outlined below.
Regardless of the construction, never operate the
cranking motor more than 30 seconds at a time without
pausing to allow it to cool for at least two minutes.
Overheating, caused by excessive cranking, will seriously
damage the cranking motor.
A general diagnosis is covered in Figure 6D-3 and 6D-4.
Once a problem has been traced to the starter, proceed to the
test procedure below.
Test Procedure
With the cranking motor removed from the engine, the
pinion should be checked for freedom of operation by turning
it on the screw shaft. The armature should be checked for
freedom of rotation by prying the pinion with a screwdriver.
Tight bearings, a bent armature shaft, or a loose pole shoe
screw will cause the armature to not turn freely. If the
armature does not turn freely the motor should be
disassembled immediately. However, if the armature does
rotate freely, the motor should be given a no-load test before
I
A M M E T E R
n
VOLTMETER
PILE
3
Fig. 6 P 4 8 No-Load Test Hook-Up
Connect a voltmeter from the motor terminal to the
motor frame, and use an RPM indicator to measure armature
speed. Connect the motor and an ammeter in series with a
fully charged battery of the specified voltage, and a switch
in the open position from the solenoid battery terminal to the
solenoid switch terminal. Close the switch and compare the
RPM, current, and voltage readings with the specifications
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