Charging System - Yanmar 1GM User Manual

ELECTRICAL SYSTEM
Alternator
CHARGING SYSTEM
(TYPICAL)
189
Battery
or other electrical emergencies. Using the cutoff switch
also prevents any electrical drain on the battery.
All engines are equipped with a 30-amp fuse installed
in the wiring harness between the ignition switch and
starter motor. If a failure occurs in any part of the electri-
cal system, always check the fuse first to see if it is blown.
Usually, the trouble is a short circuit in the wiring. This
may be caused by worn insulation or by a wire that has
worked its way loose and shorted to ground.
Treat a blown fuse as more than a minor annoyance; it
serves as a warning that something is wrong in the electri-
cal system. Before replacing a fuse, determine what
caused it to blow and correct the problem. Always carry
several spare fuses of the proper amperage values
onboard. Never replace a fuse with one of higher amper-
age rating than that specified for use. Failure to follow
these basic rules could result in heat or fire damage to ma-
jor parts or even the loss of the entire vessel.
CHARGING SYSTEM
The charging system consists of the battery, alternator,
voltage regulator, ignition switch, charge lamp and con-
necting wiring. All engines are equipped with a Hitachi
alternator. Refer to Figure 12 for a typical charging
system.
Preliminary Testing
The first indication of charging system trouble is usu-
ally a slow engine cranking speed or running lights that
dim as engine speed decreases. This will often occur long
before the ammeter or voltmeter indicates that there is a