B
ELECTRICAL
Read all of SAFETY and this section before attempting any procedure. Pay particular attention to Notices, Cautions, Warnings and Dangers.
133
Repair and Service Manual
653045
ELECTRICAL
CIRCUITS AND CONTROLS
The electrical system is a 12 volt negative ground system
consisting of:
•
Battery
•
Starter/generator
•
Voltage regulator
•
Solenoid
•
Magneto
•
Fuse
•
Key switch
To decrease the risk of injury or
death from accidental movement of
the vehicle, all tests performed
requiring the starter/generator or the engine to
rotate must be performed with the vehicle lifted (see
SAFETY section) or the neutral lock engaged (see
GENERAL INFORMATION AND ROUTINE MAINTE-
NANCE section).
Follow the lifting procedure in the SAFETY section.
Place wheel chocks in front and behind the front
wheels. Check the stability of the vehicle on the jack
stands before starting any repair procedure. Never
work on a vehicle that is supported by a jack alone.
STARTER
When starting the engine, the field coils are in series with
the armature and the starter/generator operates as a
motor. This circuit is controlled by the key switch, fuse,
accelerator limit switch and the solenoid. With the key in
the ON position, battery current is available to the accel-
erator limit switch which remains open until the accelera-
tor pedal is pressed. When the pedal is pressed, the
plunger on the switch is released, the contacts close and
the ignition circuit is energized. Battery current then ener-
gizes the solenoid which closes the contacts and ener-
gizes the starter circuit. The starter/generator now
functions as a starter to start the engine.
GENERATOR
When the engine is running, the starter/generator func-
tions as a generator. This is used for charging the battery
and for the ignition system. Generated output is con-
trolled by the voltage regulator at 14.25 - 14.75 V, without
regard to engine speed. However, the charging current
will vary depending on the condition of the battery. If it is
fully charged, current is controlled at 3 to 5 amps.
WIRING
Before performing any test of wiring
components, disconnect the battery
cables from the battery to decrease
the risk of electrical shock or explosion (see proce-
dure in SAFETY section).
Electrical tests of the wiring for continuity may be made
with a DVOM (Digital Volt Ohm Meter) available through
the Service Parts Department (P/N 27481G01). Any
DVOM may be used, however the controls, displays and
features may vary depending on the make and model.
Set the meter selector to the ohms scale and check conti-
nuity between each circuit component as indicated.
Example: If a switch is open or if there is a break in the
wiring, the meter will display a visual signal. If an analog
meter is used it will read infinity (
).
TESTING THE IGNITION CIRCUIT
NOTICE: This section assumes the fuel system is
functioning and the engine is receiving fuel.
Tool List
Qty.
DVOM ..........................................................................1
Spark Plug (NGK BPR2ES).........................................1
Spark Plug Tester ........................................................1
To decrease the risk of personal
injury, never operate the starter
unless both spark plugs are
installed or the ignition system is disabled. Fuel
drawn into the cylinders will be expelled through the
spark plug opening and could be ignited by the igni-
tion system or another source, resulting in a fire.
The engine incorporates a magneto type ignition system.
There is no distributor.
The engine can be stopped by turning the key switch to
the
OFF
position. When the accelerator pedal is released,
the limit switch contacts open and the ignition circuit is de-
energized.
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