Installation manual
DC
ELECTRICAL
SYSTEM
ALTERNATOR
1. Start the engine.
2. After the engine has run for a few minutes, measure the
starting battery voltage at the
battety terminals using a
multimeter set on DC volts.
a.
If
the voltage is increasing toward 14 volts, the alterna-
tor is working; omit
Steps 3 through 8 and go directly
to
"Checking the Service Battery" on the
next
page.
b.
If
the voltage remains around
12
volts, a problem
exists with eitl1er the alternator or the charging circuit;
continue with Steps 3 through
8.
#10
RED
BATTERY
CONNECTOR
~AT
STARTER
miD
MULTIMETER
_
_,.....0
COM
51
AMP
ALTERNATOR
SEE
WIRING
DIAGRAM
;
FOR
WIRE
CONNECTIONS.
#12BLACKTO
GROUND
AT
STARTER
ALTERNATOR
TROUBLESHOOTING
A
WARNING:
A failed alternator
can
become
very
hot.
Do
11ot
touch
until
the
alternator
has
cooled
down.
Use this troubleshooting section to determine
if
a problem
exists with the charging circuit
or
with the alternator.
If
it is
determined that the alternator
or
voltage regulator is faulty,
have a qualified technician check it.
The alternator charging circuit charges the starting battery
and the service battery. An isolator with a diode, a solenoid
or a battery selector switch is usually mounted in the circuit
to isolate the batteries so the starting battery is not discharged
along with the service battery.
If
the alternator is charging the
starting battery but not the service battery, the problem is in
the service battery's charging circuit and not with the altema-
tor.
Testing
the
Alternator
A
CAUTION:
Before
starting
the
engine
make
certain
that
everyone
is clear of
moving
parts!
Keep
away
from
sheaves
and
belts
during
test
procedures.
A
WARNING:
When
testing
with
a
multimeter:
DC
and
AC
circuits
are
often
mixed
together
in
marine
applications.
Always
disconnect
a
shore
power
cord,
isolate
DC
and
AC
converters,
and
shut
down
the
engine
before
performing
DC
testing.
No
AC
tests
should
be
made
without
a
proper
knowledge
of
AC
circuits.
35
TESTING
THE
STARTING
BATTERY/ALTERNATOR
(ENGINE
RUNNING)
3. Tum off
tl1e
engine. Inspect all
wiring_
and connections.
Ensure that the battery tenninals and the engine ground
connections are tight and clean.
A
CAUTION:
To
avoid
damage
to
the
battery
charging
circuit,
never
shut
off
the
engine
battery
switch
when
the
engine
is
running!
4.
If
a battery selector switch is in the charging circuit,
ensure that it is on the correct setting.
5. Turn on the ignition switch, but do not start
ilie engine.
6. Check the
battety voltage.
If
tl1e
battery is in good condi-
tion, the reading should be 12 to
13
volts.
TESTING
THE
ALTERNATOR
VOLTAGE
(IGNITION
ON
•
ENGINE
OFF)
@.ID
0_,__
__
.
MULTIMETER
COM+
-
GROUND