2.
3.
Connect positive (+) voltmeter lead to red/purple
lead and negative (–) voltmeter lead to ground
terminal.
4. Remove coil wire from distributor cap tower and
ground it to block. Turn on all accessories and
crank engine over with starter motor for 15-20
seconds.
Voltmeter should indicate battery voltage. If bat-
tery voltage is not present, check sensing circuit
(red/purple lead) for loose or dirty connection or
damaged wiring.
5. Turn off accessories and reinstall coil wire. Start
engine and adjust engine speed to 1500-2000
RPM. Quickly observe ammeter. Reading should
be at least 30 amps.
6.
If reading is low, stop engine and connect a jump-
er wire between alternator output terminal and
regulator terminal. Repeat Steps 4 and 5.
d
7.
If reading is now within specifications, diodes are
faulty. Disassemble alternator and replace
rectifier as explained under “Alternator Repair,”
following, to determine if fault is in regulator or
alternator.
a
e
8.
If reading is still low with jumper wire connected,
perform “Voltage Output Test,” following, to de-
termine if fault is in regulator or alternator.
c
b
a
72786
a - Output Wire - ORANGE
b - Excitation Wire - PURPLE
c - Sensing Wire - RED/PURPLE
d - Voltmeter (0-20 Volts)
e - Ground
b
e
c
d
Current Output Test
72787
Perform this test to check if alternator is capable of
producing rated current output, using a 0-50 amp DC
ammeter.
a - Output Wire - ORANGE
b - Ammeter (0-50 Amps)
c - Jumper Lead
d - Regulator Lead
e - Ground
!
WARNING
Be sure that engine compartment is well-venti-
lated and that there are no gasoline vapors pres-
ent (during the test) to prevent the possibility of
an explosion and/or a fire, should a spark occur.
Voltage Output Test
Perform this test to determine if voltage regulator is
operating correctly, using a 0-20 volt DC voltmeter.
1.
2.
Disconnect negative (–) battery cable from bat-
tery.
IMPORTANT: Battery MUST BE fully charged
(1.260
or above specific gravity) to obtain proper
voltage reading in this test. If necessary, charge
battery with a battery charger or allow engine to
run a sufficient length of time to fully charge bat-
tery before taking reading.
Disconnect orange lead from alternator output
terminal and connect ammeter in series between
lead and output terminal. Connect positive (+)
side of ammeter toward output terminal.
3.
Reconnect negative battery cable.
Index
4C-6 - CHARGING SYSTEM
90-823224--2 796
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1993, 1994, 1995, 1996, 1997 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
(4 votes, average: 4.5 out of 5)
Marine readers have rated 1993 1997 Mercury-MerCruiser GM V8 454 CID 7.4L and 502 CID 8.2L Marine Engines Service Manual Number 16 4.5 out of 5.0 based on 4 product reviews. Hugely helpful service manual! Perfect. Thank you!
Manuals are all Important for Technician
This book is invaluable if you do your own repairs. Great book.
Could not find a copy until a search brought me here.
Excellent print.
Thank you