Mercury 100 FourStroke, Service Manual

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2B-6 - ELECTRICAL 90-830234R3 DECEMBER 1997
10. A reading of 16 amperes (or 12 amperes for 15
ampere stator) at 3500 RPM indicates the charg-
ing system is functioning properly. The battery is
discharging due to the amperage draw on the
system is greater than the amperage output of
the engine charging system.
11. If ammeter reads less than 18 amperes or 12 am-
peres respectively, test the stator; refer to “Stator
Ohms Test (Alternator Coils Only)”, [18 Ampere
Stator], preceding. If stator tests OK, replace volt-
age regulator/rectifier.
Tachometer Terminal Block
DESCRIPTION
This block is a junction point for stator and tachome-
ter signal wiring. It contains no electrical compo-
nents. This block is LIGHT GREY in color and is to be
used ONLY with small, non-finned voltage regula-
tors. No test is required for this terminal block.
ALT YEL
ALT YEL
GREY
TACH
50644
Tachometer Terminal Block
REMOVAL
1. Remove two YELLOW alternator wires from
block.
2. Remove GREY tachometer wire from block.
3. Remove two attaching screws and remove diode
block.
INSTALLATION
1. Secure diode block to powerhead with two
screws. Torque screws to 30 lb. in. (3.4 N m).
2. Attach two YELLOW wires to “ALT YEL” termi-
nals.
3. Attach GREY wire to “GREY TACH” terminal.
RED Stator Battery Charging System
Troubleshooting
MODELS EQUIPPED WITH REGULATOR (RED
STATOR)
a
b
c
d
a - Stator
b - Voltage Regulator/Rectifier
c - Start Solenoid
d - 12V Battery
The charging system may be damaged by: 1) re-
versed battery cables, 2) running the engine with bat-
tery cables disconnected and stator leads connected
to rectifier, and 3) an open circuit, such as a broken
wire or loose connection.
A fault in the battery charging system usually will
cause the battery to become undercharged. Check
battery electrolyte level, and charge battery. See
“Electrolyte Level”, and “Charging a Discharged
Battery”.
If battery will NOT accept a satisfactory charge, re-
place 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 incor-
rect, check for damaged rectifier. See “Rectifier
Test”, following.
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.