TOPIC 4. STARTER MOTOR

TM 10-3930-644-14&P

TOPIC 4. STARTER MOTOR

A. DESCRIPTION

responds instantly and cranks engine when the

ignition switch is closed, the starter motor may

The starter motor is designed to operate under overload

be considered to be in satisfactory working

conditions and to produce high torque. Because of its

condition.

limited physical size it can only do this for short periods

of time, since in order to produce such power a high

NOTE

electrical current must be used. High current creates

The starter motor is equipped with

considerable heat and if the starting operation is

graphite

and

oil

impregnated

continued for any length of time, the accumulated heat

bushings which should be lubricated

will cause serious damage.

only when motor is disassembled.

C. REMOVAL

CAUTION

Starter must never be used for more

1. Lift operator's seat and swing open side panel.

than 30 seconds at any one time.

Allow starter motor to cool for 2

2. Disconnect battery cable leads at battery to

minutes before using again. Never

guard against possible electric shock during

use starter to move truck.

removal.

The drive mechanism incorporates a locking feature

which prevents demeshing of the drive pinion from the

3. Disconnect and label all electrical connections at

flywheel ring gear, until a predetermined flywheel speed

starter motor.

is reached. The automatic meshing of the drive pinion

with the flywheel ring gear is accomplished in the usual

4. Remove mounting bolts which secure starter

manner. If the engine fails to continue running, due to

motor to flywheel housing.

weak or irregular firing, premature demeshing of the

pinion from the ring gear is prevented by the locking

5. Carefully pull starter motor assembly out of

feature.

flywheel housing until drive end clears flywheel

housing, then tilt commutator end up to remove

A magnetic solenoid switch is used in the starter motor

unit from truck.

circuit since It uses less electrical current, and allows

use of a starter switch and lighter gauge wiring. The

NOTE

starter solenoid is mounted on the starter housing.

For DISASSEMBLY, INSPECTION, RE-PAIR

and REASSEMBLY, refer to REPAIR

The starter motor is a completely enclosed unit and

MANUAL.

requires very little maintenance. However, to ensure

satisfactory operation, periodic inspections should be

D. INSTALLATION

made to make sure mounting and wiring connections are

tight and in good condition.

1. Insert drive end of starter motor in flywheel

housing. If drive mechanism is fully extended,

B. INSPECTION

then mesh pinion gear with flywheel ring gear.

1. Verify that starter motor electrical connections to

2. Install mounting bolts and tighten securely.

battery are clean and tight.

3. Connect all electrical leads to starter motor as

labeled.

NOTE

Loose or dirty connections anywhere

4. Connect battery positive lead to positive post

in the electrical circuit will cause high

and negative lead to negative post.

resistance and reduced cranking

efficiency.

5. Close side panel and lower operator's seat.

2. When all mounting and wiring connections are

kept in good condition, and the starter motor

M-146-1

2-27