Alternator System Circuitry Test; Output Circuit; Sensing Circuit - Mercury Optimax 115 Service Manual

Alternator System Circuitry Test

Using a 0-20 volt DC voltmeter, perform the following tests:

Output Circuit

1. Connect POSITIVE (+) voltmeter lead to alternator terminal B (output terminal). Con-
nect NEGATIVE (–) lead to case ground on alternator.
2. Shake alternator wiring harness. Meter should indicate battery voltage and should not
vary. If proper reading is not obtained, check for loose or dirty connections or dam-
aged wiring.
a -

Sensing Circuit

1. Unplug RED and PURPLE lead connector from alternator.
2. Connect POSITIVE (+) voltmeter lead to RED lead and NEGATIVE (–) voltmeter lead
to ground.
3. Voltmeter should indicate battery voltage. If correct voltage is not present, check
sensing circuit (RED lead) for loose or dirty connections or damaged wiring.
a -
90-855347R1 JANUARY 1999
2030 40 60
5 10 15
OHMS
100
0
200
20
30
15 10 5 10
40
20
8 6 4 0 0
10 2
VOLTS
0
DC AMPS
DCV
ACV
DVA
Terminal B
Sense Lead (RED)
CHARGING & STARTING SYSTEM
a
a
56113
a
a
56114
Page 2B-13