Mercury 40 Service Manual page 82

1. Check for correct battery polarity [red cable to
positive (+) battery terminal]. If polarity was incor-
rect, check for damaged rectifier. See "rectifier
test", later in this section.
2. Check for loose or corroded battery connections.
3. Visually inspect wiring between stator and bat-
tery for cuts, chafing, and disconnected, loose or
corroded connection.
4. Excessive electrical load (from too many acces-
sories) will cause battery to run down.
If visual inspection determines that battery connec-
tions and wiring are OK, perform the following stator
and alternator systems tests.
90-852572R1 JANUARY 1998
STATOR OHMS TEST
(ALTERNATOR COILS ONLY)
NOTE: Stator can be tested without removing from
engine.
1. Disconnect both yellow (stator leads) from volt-
age regulator/rectifier, or terminal block.
2. Use an ohmmeter and perform the following test.
IMPORTANT:
If stator is mounted on engine, black
stator lead (if provided) must be grounded to power-
head when testing.
Replace stator if readings are outside ranges
3.
shown.
NOTE: Resistance varies greatly with temperature.
Measurements should be taken with an ambient tem-
perature range of 65 to 85 F.
9 Ampere Manual Stator
Resistance
Test Leads
Between Yellow
0.16 - 0.19*
Stator Leads
Between Either
Yellow Stator Lead
No Continuity
and Engine
Ground
* DC Resistance of these windings generally is less than
1.5 Ohms. If a reading resembling a short is obtained, this
would be acceptable.
16 Ampere Stator
Resistance
Test Leads
Between Yellow
0.16 - 0.19*
Stator Leads
Between Either
Yellow Stator Lead
No Continuity
and Engine
Ground
* DC Resistance of these windings generally is less than
1.5 Ohms. If a reading resembling a short is obtained, this
would be acceptable.
Scale
(Ohms) Reading
R x 1
R x 1000
Scale
(Ohms) Reading
R x 1
R x 1000
ELECTRICAL - 2B-7