Evinrude E-tec 75 HP, Service Manual

Page: 131 / 344

131
ELECTRICAL AND IGNITION
CHARGING SYSTEM TESTS
6
Following the manufacturer’s directions, connect
the variable load tester (carbon pile) across the
battery terminals.
Stevens
model LB-85 and
Snap-on
model MT540D are examples of testers
available.
Start the outboard and run it at approximately
5000 RPM. Use the variable load tester to draw
the battery down at a rate equivalent to the sta-
tor’s full output.
•
The ammeter should indicate nearly full output,
Approximately 25 A @ 5000 RPM.
Decrease the battery load toward 0 A.
•
Ammeter should show a reduced output. As the
current draw decreases, the battery voltage
should stabilize at approximately 14.5 V.
•
If results vary, check stator BEFORE replacing
the
EMM
. See Stator Tests on p. 129.
55 V Alternator Circuit
STEP 1
Check battery ground cable for continuity.
STEP 2
With the key switch ON, check battery voltage at
battery, then check voltage on white/red wires at
J2 connector of
EMM
. Voltage at
EMM
connector
should be 0.5 to 1 V less than battery.
STEP 3
With outboard running at 1000 RPM, voltage on
white/red wires should increase to 55 V.
Voltage readings at a specific speed (RPM)
should be steady.
If there is any other reading, perform Stator
Resistance Tests on p. 129 and Stator Voltage
Output Test on p. 129. Inspect the stator wiring
and connections. Inspect the capacitor wiring,
connections, and capacitor. Repair the wiring or
replace a faulty capacitor, stator, or
EMM
.
WARNING
Excessive battery discharge rates might
overheat battery causing electrolyte gas-
sing. This might create an explosive atmo-
sphere. Always work in a well ventilated
area.
Variable Load Test Diagram
1. Red wire (alternator output from
EMM
)
2. Starter solenoid
3. Battery cable terminal (B+)
4. Variable load tester
5. Ammeter
002077
Battery Charging Graph 002076
2
1
5
4
3
75 – 90 HP
1. J2 connector of
EMM 002291
1