Installation manual
DC
ELECTRICAL
SYSTEM
7. Now check the voltage between the alternator output ter-
minal (B+) and ground.
If
the circuit
is
good, the voltage at
the alternator will
be the same as the battery, or
if
an isola-
tor
is
in the circuit the alternator voltage will be zero.
If
neither
of
the above
is
true, a problem exists in the circuit
between the alternator and the battery. Check all the
connections - look for an opening
in
the charging circuit.
TESTING
THE
STARTING
BATTERY
IALTERNATOR
(ENGINE
RUNNING)
M
ULTIMETER
WITCH
~~a+"
I
CI2ID
0
COM
I'
"\..
ENGIN
E
GROUND
8. Start the engine again. Check the voltage between the
alternator output and ground.
The voltage reading for a properly operating alternator
should be between 13.5 and 14.5 volts.
If
your alternator
is
over- or under-charging, have it repaired at a reliable
service facility.
NOTE:
Before removing the alternator
for
repair;
use a
voltmeter to ensure that
12 volts
DC
excitation is present
at
the EXC terminal
if
the previous test showed only bat-
tery voltage
at
the B output terminal.
If
12
volts is not present
at
the
EXC
terminal, trace the
wiring
and
look
for
breaks
and
poor
connections.
12
VOLT
DC
CONTROL
CIRCUIT
The engine has a 12 volt DC electrical control circuit that
is
shown on the wiring diagrams that follow. Refer to these
diagrams when troubleshooting or when servicing the
DC
electrical system.
A
CAUTION:
To
avoid
damage
to
the
battery
charging
circuit,
never
shut
off
the
engine
battery
switch
while
the
engine
is
running.
Shut
off
the
engine
battery
SWitch,
however,
to
avoid
electrical
shorts
when
working
on
the
engine's
electrical circuit.
BAnERY
The minimum recommended capacity
of
the battery used
in
the engine's
12
volt DC control circuit
is
600 - 900 Cold
Cranking Amps (CCA).
Checking
the
Service
Battery
Check the voltage
of
the service battery. This battery should
have a voltage between
13
and 14 volts when the engine
is
running.
If
not, there
is
a problem in the service battery
charging circuit. Troubleshoot the service battery charging
circuit by checking the wiring and connections, the solenoid,
isolator, battery switch, and the battery itself.
MumMETER
i
COM
GROUND
SERVICE
BATTERY
TESTING
THE
SERVICE
BATTERY
(ENGINE
RUNNING)
A
CAUTI,ON:
To
avoid
damaging
the
alternator
diodes,
do
not
use
a
high
voltage
tester
(i.e.
a
megger)
when
performing
tests
on
the
alternator
charging
circuit.
Battery
Care
Review the manufacturer's recommendations and then
establish a systematic maintenance schedule for your
engine's starting batteries and house batteries.
o Monitor your voltmeter for proper charging during
engine operation.
o Check the electrolyte level and specific gravity with a
hydrometer.
o Use only distilled water to bring electrolytes to a proper
level.
o Make certain that battery cable connections are clean and
tight to the battery posts (and to your engine).
o Keep your batteries clean and free
of
corrosion.
A
WARNING:
Sulfuric
acid
in
lead
batteries
can
cause
severe
bums
on
skin
and
damage
clothing.
Wear
protective
gear.
Engines & Generators
25