Mercury 40 Service Manual page 83

ALTERNATOR SYSTEMS TEST
9 Ampere Manual Stator
IMPORTANT: Rectifier (optional accessory) must
be functioning properly for accurate test results
to be obtained.
Remove RED lead from (+) terminal of rectifier.
1.
Connect RED (+) ammeter lead to rectifier (+) ter-
2.
minal and BLACK (–) ammeter lead to RED recti-
fier lead.
With engine running at the indicated RPM, the
3.
ammeter should indicate the following approxi-
mate amperes:
RPM
9 Ampere 9 Ampere
1000
Manual Stator Manual Stator
2000
3000
If proper ampere readings are not obtained, re-
4.
place stator.
16 Ampere Stator
1. Check battery voltage at battery with engine run-
ning.
2. If battery voltage is above 14.5 volts, replace volt-
age regulator/rectifier. Check condition of battery
as overcharging may damage battery.
3. If battery voltage is below 14.5 volts, charge bat-
tery; refer to "Charging a Discharged Battery",
preceding. If battery can not be satisfactorily
charged, replace battery.
4. If battery accepts a satisfactory charge, check
battery voltage while cranking engine; refer to
"Charging a Discharged Battery", preceding. If
cranking voltage is not acceptable, replace battery.
If cranking voltage is acceptable, disconnect
5.
larger diameter RED harness wire from starter
solenoid terminal.
2B-8 - ELECTRICAL
AMPERES
Idle 0
0.6
8.0
9.0
Remove RED sense lead wire from starter sole-
6.
noid terminal and connect to the positive (+) ter-
minal of a 9 volt transistor battery. Ground the
negative (–) terminal of the 9 volt battery to the
engine.
a - Red Sense Lead (Female Connector)
Connect RED (+) ammeter lead to larger diame-
7.
ter RED harness wire, and BLACK (–) ammeter
lead to POSITIVE terminal on starter solenoid.
Secure starter wires away from flywheel.
8.
9. With engine running at the indicated RPM's, the
ammeter should indicate the following approxi-
mate amperes:
RPM
Idle
16 Ampere
Stator S
1000
2000
A reading of 16 amperes at 2000 RPM indicates
10.
the charging system is functioning properly. The
battery is being discharged because of the
excessive amperage draw on the system (the
draw is greater than the amperage output of the
engine charging system).
If ammeter reads less than required amperes @
11.
3000 RPM, test the stator; refer to "Stator Ohm
Test (Alternator Coils Only)". If stator tests OK,
replace voltage regulator.
a
AMPERES
2.8
9.3
16
90-852572R1 JANUARY 1998