Service Manual

Part Numbers
NN10739
Purpose
The starter motor pushes the starter pinion into engagement with the
flywheel, then rotates the starter motor to start the engine.
How It Works
The starter motor is really just a collection of simple parts:
FIELD: A coil of wire on an iron core that becomes an electromagnet when
current is applied. It surrounds the armature.
ARMATURE: Eight coils of wire on an iron core that become
electromagnets when current is applied. The end of each coil is connected
to a section of the commutator. The armature rotates.
COMMUTATOR: The commutator is the connection point between the
brushes and the coils in the armature. The sections are divided such that
only one armature coil is “on” at a time. This sets the armature to rotating
because the electromagnetic field in the field coil will oppose the one in the
armature.
BRUSHES: Supply power to the commutator.
Testing
With the starter assembled, disconnect the connecting lead from the
starter solenoid C terminal. Connect a jumper lead from the connecting
lead to the battery positive terminal. Connect a jumper lead momentarily
between the starter motor housing and the battery negative terminal. If the
motor doesn’t run, check the motor for problems.
Starter
Electric
Solenoid
Mounting Nut
Through
Bolts
Magnet Switch
Mounting Nuts
Starter Drive
Housing
Connecting
Lead
Brush
Insulator
Brush Holder
Brush Spring
End Frame
Starter Body
Glossary
GLOSSARY
Demystification Guide 3-23