Battery Charging System Troubleshooting; Stator Ohms Test (Alternator Coils Only) - Mercury 45 Jet 50-55 Service Manual

Battery Charging System
Troubleshooting
A fault in the battery charging system usually will cause the
battery to become undercharged. Check battery electro-
lyte level, and charge battery. See "Electrolyte Level", and
"Charging a Discharged Battery".
If battery will NOT accept a satisfactory charge, replace
battery.
If battery accepts a satisfactory charge, determine the
cause of the charging system problem as follows.
1. Check for correct battery polarity [red cable to positive
(+) battery terminal]. If polarity was incorrect, check for
damaged rectifier. See "Rectifier Test".
2. Check for loose or corroded battery connections.
3. Visually inspect wiring between stator and battery for
cuts, chafing; and disconnected, loose or corroded
connection.
4. Excessive electrical load (from too many accessories)
will cause battery to run down.
If visual inspection determines that battery connections
and wiring are OK, perform the following stator and rectifier
tests.
2B-4 - ELECTRICAL and IGNITION
Stator Ohms Test
(Alternator Coils Only)
NOTE: Stator can be tested without removing from engine.
1. Disconnect both yellow (stator leads) from voltage reg-
ulator/rectifier, or terminal block.
2. Use an ohmmeter and perform the following test.
IMPORTANT: If stator is mounted on engine, black sta-
tor lead (if provided) must be grounded to powerhead
when testing.
3. Replace stator if readings are outside ranges shown.
NOTE: When servicing a unit listed "Serial Number and
Below", it is recommended that the flywheel be removed
and the stator part number verified to determine proper
testing applications.
55/60 MARATHON/SEAPRO – (398-9873A-5 or
398-9873A21 printed on the stator)
LIGHTING COIL STATOR - 7 AMPERE (96 WATTS)
Test Leads Resistance
(OHMS)
Between Yellow .12 – .23*
Stator Leads
Between Either
Yellow Stator No Continuity
Lead and Engine
Ground**
Between Blue/
White and Black 100 – 140
Stator Leads
* DC Resistance of these windings generally is less than 1.5 OHMS.
If a reading (resembling a short) is obtained, this would be accept-
able.
** If stator is removed from engine, connect test lead to black stator
lead, if provided.
45 JET, 50/60 ELECTRIC – (398-9710A22,
398-9710A23, or 398-9710A34 printed on the stator)
USA S/N 0G277605 and BELOW
BELGIUM S/N (Not Available at Time of Printing)
9 AMPERE STATOR
Test Leads Resistance
(OHMS)
Between Yellow .6 – 1.1*
Stator Leads
Between Either
Yellow Stator No Continuity
Lead and Engine
Ground**
Scale Reading
(x_______)
.12 – .23*
(R x 1)
No Continuity
(R x 1000)
10 – 14
(R x 10)
Scale Reading
(x_______)
.6 – 1.1*
(R x 1)
No Continuity
(R x 1000)
90-817643R1 DECEMBER 1996