Service Manual

How It Works
The starter motor is really just a collection of simple parts:
FRAME: Houses the permanent magnets which produce a magnetic field.
This field surrounds the armature and causes it to rotate.
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.
Troubleshooting Guide
PROBLEM POSSIBLE FAULT CORRECTION
STARTER
FAILS
TO ENERGIZE
WIRING
1. Clean corroded connections and tighten loose connections.
2. Replace wires in poor condition and with frayed or broken
insulation.
STARTER SWITCH
OR SOLENOID
Bypass the switch or solenoid with a jumper wire. If starter
cranks normally, replace the faulty parts.
BATTERY Check specific gravity of battery. If low, recharge or replace
battery as necessary.
STARTER
ENERGIZES
BUT TURNS
SLOWLY
BATTERY Check specific gravity of battery. If low, recharge or replace
battery as necessary.
BRUSHES
Check for excessively dirty or worn brushes and commutator.
Clean using a coarse cloth (not emery paper). Replace brushes
if excessively or unevenly worn.
TRANSMISSION
OR
ENGINE
Make sure the clutch or transmission is disengaged or placed in
neutral. This is especially important on equipment with
hydrostatic drive. The transmission must be exactly in neutral to
prevent resistance which would keep the engine from starting.
Check for seized engine components such as bearings,
connecting rod, and piston.
Glossary
GLOSSARY
3-22 Demystification Guide