Starter Motor; Troubleshooting - Westerbeke 5.5 EGCD 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
reacli
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 ":'ith 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 tel111IDal 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 tenniniu on
the solenoid.
If tlie starter cranks, the fault lies with the ignition circuit
If the solenoid clicks but nothing else happens, the starter
motor is probably faulty.
SOLENOID
IGNffiON
TERMINAL
~
. H nothing at all happens the solenoid isn't getting current
, Check the battery isolation switch and inspect the wiring
connections. It is also possible that the solenoid is defective.
A
WARNING:
There will be arching and sparks will
fly when .jumping terminals. Be certain.fhe engine
space is
free
of potentially explosive fumes, especially
gasoline.
Engln_es & Generators
20