Evinrude & Johnson E75DPLSCB, Service Manual, Page: 140 / 349

138
ELECTRICAL AND IGNITION
TACHOMETER CIRCUIT TESTS
LOW OIL Circuit Test
Turn the key switch ON. Using a jumper wire, con-
nect tan/black wire (pin 4) of the engine harness
connector to a clean engine ground. The LOW
OIL light should turn on after 40 seconds.
If the LOW OIL light does not turn on after con-
necting the terminal to ground, test circuit for con-
tinuity.
Turn the key switch OFF and reconnect all discon-
nected circuits.
NO OIL Circuit
Separate the 6-pin SystemCheck connector of
MWS instrument harness from engine harness.
Black wire (pin 3) must be grounded.
Using a jumper wire, connect tan/yellow wire (pin
5) to a clean engine ground.
Turn the key switch ON. After the normal self-test
sequence, the NO OIL light should stay on.
•
If the NO OIL light is not on, test circuit for conti-
nuity. Test for continuity of the MWS instrument
harness (tan/yellow wire).
•
Test for continuity of the engine wire harness
between terminal 5 (tan/yellow wire) of the
Sys-
temCheck connector and pin 24 of the EMM J1-
A connector.
Turn the key switch OFF and reconnect all discon-
nected circuits.
TACHOMETER CIRCUIT
TESTS
Check voltage at the battery. Use this reading as
a reference for battery voltage.
Connect the red meter lead to the tachometer pur-
ple wire and the black meter lead to the tachome-
ter black wire (key ON, outboard NOT running).
•
If meter shows battery voltage, go to next step.
•
If meter shows less than battery voltage, check
the purple, red/purple, and black wiring circuits;
fuse, key switch, and battery connections.
Disconnect gray and black wires at tachometer.
Set
Fluke 29 Series II meter, or equivalent, to Hz
scale. Connect meter between gray wire and
black wire. With outboard running at 1000 RPM,
meter should indicate 90 to 105 Hz.
•
If meter reads 90 to 105 Hz, replace tachome-
ter.
•
If meter reads low or no signal, confirm output
on gray wire at pin 16 of
EMM J1-A connector.
– Reading OK – Check condition of tachometer
circuit (gray wire). Repair as needed.
– Reading not OK – Check connection at EMM ;
replace faulty EMM .
002079
1. Purple lead
2. Black lead
3. Gray lead
006551
2
1
3