Section III. ELECTRICAL SYSTEM, ENGINE
128. Starter
a. The starter motor supplies the necessary amount of torque for a short period of time to crank the
engine. It is a series-wound, four-pole type and transmits power to the flywheel through aBendix drive. The
starter motor consists of five major sub-assemblies; commutator head, frame and field, armature, drive and
pinion housing.
b. Removal. Remove the starter motor as described in (para. 82).
c. Testing Assembled.
(1) Load test. Connect a voltmeter (9, fig.35), knife switch (8), ammeter (1).variable resistor (2) and a
24-volt power source to starter motor as illustrated in (fig. 35). Attach a spanner wrench (5) to the
drive pinion (6). Hang a scale (4) to a support strong enough to hold 5 pounds. Attach the scale to
the spanner wrench at a point 12 inches from the center of the drive pinion (6). Close the knife
readings must be 70 amperes. Maximum 6 volts and 3.3 foot-pounds minimum. Open the knife
switch (8). If the starter motor does not test as specified it must be repaired.
Caution: Always connect highest range of ammeter into circuit for initial test because the heavy current
encountered when a shorted or grounded field exists, or when a shorted or grounded armature exists.
(2) No-load tests. Remove the scale (4, fig. 35) and spanner wrench (5). Close the knife switch (8) and
note the readings on the ammeter (1) and voltmeter
1
Ammeter
6
Drive pinion
2
Variable resistors
7
Terminal
3
Batteries
8
Knife switch
4
Scale
9
Voltmeter
5
Spanner wrench
10
Ground terminal
A Test diagram
Figure 35. Starter motor.
AGO l871A
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