battery cable connections to starter and
three screws which secure housing (16,
figure 13-4) to engine. Tag and remove
wires to the pilot relay (6, figure 13-4).
Inspection. Remove inspection plug (102, figure
13-4). If any brush is less than 3/8 inch (9.5 mm)
long, the complete set of brushes should be
Test. Testing of the starter motor assembly
consists of a no-load test of the complete unit and
component tests to determine part serviceability.
Before conducting the no-load test check the
armature for freedom of rotation. Use a screw
driver to turn the pinion on the exposed drive
assembly (25, figure 13-4) in the drive housing
(16). Tight bearings, bent armature shaft, or a
loose pole shoe screw will cause armature
binding. If the armature does not turn freely,
disassemble the unit immediately. If the
armature rotates freely, conduct the no-load test
below before disassembling the motor.
Do not allow the starter motor to operate more than
30 seconds. Allow it to cool at least two minutes
before reenergizing the motor. Overheating will
damage the motor.
Connect the starter assembly as
shown in figure 13-5.
Close the switch and vary the
carbon pile to obtain 20 volts on the
Starter motor speed at a
minimum current draw of 95 amps shall be
5500 rpm. Motor speed at the maximum
current draw of 120 amps shall be 7500
Low speed and high
current draw indicate armature drag
caused by tight, dirty or worn
bearings, bent armature shaft or
loose pole shoes, a shorted or
grounded armature and fields.
Failure to operate with
high current draw indicates a direct
ground in the terminal or fields.
Failure to operate with no
current draw indicates an open field
circuit, open armature coils, broken
brush' springs, worn brushes, high
insulation between commutator bars
or other conditions resulting in poor
contact between the brushes and
Low speed and low
current draw indicates high internal
resistance due to poor connections,
defective leads or a dirty commutator.
High speed and high
current draw indicate shorted fields.
Replace the field coil assembly and
retest the motor.
Disassemble the starter motor,
inspect and test components as necessary.
Disassembly. Disassemble the starter motor
only to the extent necessary to repair or replace
defective parts. Disassemble in accordance with
Note the relative positions of the
nose housing (16), lever housing (37), and
solenoid switch (36) so that the motor can
be reassembled in the same manner.
Tag and disconnect the field coil
connector from the solenoid M terminal and
lead from the ground terminal.
Remove four screws and