Installation manual
ALTERNATORS 
TESTING/TROUBLESHOOTING 
TESTING 
THE 
EXCITATION 
CIRCUIT 
1.  Connect 
the 
positive (+) multimeter probe 
to 
the 
excit~tion 
terminal R 
on 
the 
alternator 
and 
the negative 
(-) lead 
to 
ground. 
2. 
Turn the battery switch to the 
on 
position 
and 
note 
the multimeter reading. 
The 
reading should be 
1.3 
to 
2.5 
volts 
(see 
illustration). 
TESTING 
THE 
EXCiTATION 
J~IRCUJT 
(IGNITION 
UIVl'-~il 
3. 
If 
the reading is hetween 
.75 
and 
1.1 
volts, 
the 
rotor 
field 
circuit probably 
is 
shorted 
or 
wpunded. 
4. 
If 
the reading 
is 
between 
6.0 
and 7.0 volts, the rotor 
field 
circuit probably 
is 
open. 
. 
5. 
If 
no reading is obtained, 
an 
open 
eXists 
in 
the 
alternator-excitation lead 
or 
in the excitation circuit of 
the regulator. Disconnect 
the 
lead 
from 
exe. 
terminal 
R. 
Connect the'positive multimeter probe 
to 
the 
excitation 
lead 
and 
the negative multimeter probe to ground. 
If 
the 
multimeter 
now 
indicates 
an 
approximate battery 
voltage, the voltage regulator is defective 
and 
must 
be 
replaced. If 
no 
voltageJs indicated, check the 
excitation circuit for 
loose 
or 
dirty connectlons or. 
damaged 
wiring. 
TERMINAL 
R 
. 
TESTING 
THE 
EXCITATION 
CIRCUIT 
(IGNITION 
ON) 
(+) 
CHECKING 
THE 
SERVICE 
BATTERY 
Check 
the 
voltage 
of the 
service 
battery. 
lhis 
battery 
shOuld 
have 
.voltage between 
13 
and 
14 
volts 
when 
the 
engine 
is 
running. 
If 
not, 
there 
is a 
pro.b1em 
in 
the 
service 
battery 
charging 
circuit. 
Troubleshoot.the 
service 
battery 
eharging 
circuit 
·by 
checking 
the 
wiring 
and 
connections, 
the 
solenoid, 
isolator, 
battery 
switch, 
and 
the 
battery 
itself. 
When 
the 
problem 
has 
been 
solved 
and 
before 
the 
alternator 
. 
is 
back 
in 
operation, 
take 
the 
time 
to 
tighten· 
and 
clean 
the 
terminal 
studs. 
Also 
clean 
the 
connecting 
terminals 
from 
the 
wiring 
harness. 
ALTERNATOR 
REPAIR 
If 
tests 
indicate a 
failed 
alternator, 
it 
will 
need 
to 
be 
disas-
sembled 
and 
repaired. 
Any 
good 
alternator 
service 
shop 
can 
do 
the 
job. 
NIiTE: 
WESTERBEKE'S 
service 
Manual 
has 
detailed 
instructions 
for 
the 
disa"sembly 
and 
repair 
of 
their 
staridard 
alternators. 
· 
BATTERY 
CARE 
The 
minimum 
recommended 
capacity 
of 
the 
battery 
used 
in 
· 
the 
engine's 
12 
volt 
DC 
control 
circuit 
is 
600 
- 900 
C;old 
Cranking 
Amps 
(CCA). 
· 
Review 
the 
manufacturer's 
recommendations 
lind 
thel). 
establish 
a systematic 
maintenance 
schedule 
for·yout 
engine's starting batteries 
and 
house 
batteries. 
• 
Mouitor 
your voltmeter for 
proper 
charging 
during 
engine 
operation. 
• 
Check 
the 
electrolyte 
level 
and 
specific 
gravity 
with 
a 
hydrometer. 
• 
Use 
ouly 
distilled water 
to 
bring 
electrolytes 
to 
a 
proper 
level. 
•. 
Make 
certain that 
battery 
cable 
connections 
are 
clean 
and 
tight 
to 
the 
battery 
posts 
(and 
to 
your 
engine). 
• 
Keep 
your batteries 
clean 
and 
free 
of 
corrosion. 
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 
CAUTION: 
To 
avoid 
damage 
to 
the 
battery 
charging 
circuit, 
never 
shut 
off 
the 
engine 
battery 
switch 
when 
the 
engine 
Is 
running! 
~ 
WESTERBEICE 
Engines & Generators 
27 










