Starter Motor; Troubleshooting - Westerbeke 7.6 EGTD Operator's Manual

STARTER MOTOR
DESCRIPTION
The starting system includes the battery, starter motor, solenoid,
and the start toggle switch.
When the start switch on the instrument panel is depressed,
current flows and energizes the starter's solenoid coil. The
SOLENOID
energized coil becomes an electromagnet, which pulls the plunger · IGNITION
into the coil, and closes a set of contacts, which allow high current . TERMINAL
to reach the starter motor. At the same time, the plunger also serves
to push that starter pinion to mesh with the teeth on the flywheel.
To prevent damage to the starter motor when the engine starts, the
pinion gear incorporates an over-running (one-way) clutch which
is splined to the starter armature shaft The rotation of the running
engine may speed the rotation of the pinion but not the starter
motor itself.
Once the start switch is released, the current flow ceases, stopping
the activation of the solenoid. The plunger is pulled out of
contact with the battery-to-start cables by a coil spring, and the
flow of electricity is interrupted to the starter. This weakens the
magnetic fields and the starter ceases its rotation. As the solenoid
plunger is released, its movement also pulls the starter drive
g~
from its engagement with the engine fly-wheel. .
TERMINALS
>-
SOLENOID
MOTOR
TYPICAL
STARTER MOTOR
REFER TO THE WIRING
DIAGRAM IN THIS MANUAL
TROUBLESHOOTING
Prior to testing, make certain the batteries are at a full charge
and that the starting system wiring connections (terminals) are
clean and tight. Pay particular attention to the ground wire
connections on the engine block.
To check the wiring,
try
cranking the starter for a few seconds,
never more than 10 seconds at a time, then run your hand along
The wires and terminals looking for warm spots that indicate
resistance. Repair or replace any trouble spots.
Using a multimeter, test the voltage between the positive terminal
stud on the start solenoid and the engine block (ground).
If you read 12 volts, the starter is faulty.
n
To
test
the ignition circuit, locate the ignition(s) terminal (it is one
of the small terminal studs and is wired
to
the ignition circuit).
Use a screwdriver, don't touch the blade, to jump from that
ignition terminal to the positive battery connection terminill on
the solenoid.
If
the
starter cranks, the fault lies with the ignition circuit
If
the solenoid clicks but nothing else happens, the starter
motor is probably faulty.
SOLENOID
IGNITION
TERMINAL
~
. If nothing at all happens the solenoid isn't getting current
, Check the
battery
isolation switch and inspect the
wiring
cmmections. It is also possible
that
the solenoid is defective.
A
WARNING:
There will be arching and sparks will
fly when jumping terminals. Be certain·the engine
space is free of potentially explosive fumes, especially
gasoline.
Engines & Generators
20