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ENGINE MANAGEMENT MODULE (EMM)
EXTERNAL SENSORS
Crankshaft Position Sensor
Ribs spaced on the flywheel mark crankshaft posi-
tion. As the ribs pass the magnetic field of the
CPS, an AC voltage signal is generated. The
EMM uses this signal to identify crankshaft posi-
tion and speed, generate a tachometer signal, and
control fuel and ignition timing.
If the sensor is damaged or the signal is intermit-
tent:
• Below 2000 RPM: 5 occurrences
• Above 2000 RPM: 1 occurrences
the EMM:
Approximate air gap between CPS and flywheel
encoder ribs is 0.073 (1.85 mm).
Use the Evinrude Diagnostics software Monitor
screen to check CPS operation. The software
should show an RPM reading while the outboard
is cranking. If the CPS or its circuit fails, no RPM
reading will appear and the outboard cannot run.
Knock Sensor
Knock sensors (one per cylinder head) detect the
presence of knock (pre-ignition or detonation) dur-
ing the combustion cycle.
When knock is detected, the EMM temporarily
increases fuel flow and retards ignition timing for
the affected cylinder.
If knock continues, the EMM:
If the sensor circuit is OPEN, the EMM:
Neutral/Shift Interrupt Switch
A switch mounted on the powerhead signals the
EMM when the shift linkage is moved from FOR-
WARD or REVERSE into NEUTRAL.
A cam on the powerhead shift arm closes the
switch in NEUTRAL, completing a ground circuit
to the EMM. This signal is used to control:
• Neutral RPM limit
• Shift Interrupt function.
The shift interrupt function shuts off fuel and spark
to three cylinders for approximately one second to
reduce drivetrain loads and ease shifting, then
immediately restores normal engine operation.
The switch must be released to its open position
before the shift interrupt function can be activated
again. This circuit does not function above 2500
RPM.
If the switch is stuck in the closed position, the
EMM:
Stores service code 16
EMM LED 2: OFF (Cranking)
EMM LED 3: ON (Running)
Activates S.A.F.E.
Stores service code 1-6 (code indicates cyl)
Engine Monitor CHECK ENGINE display: ON
Stores service code 7 (port sensor)
Stores service code 8 (stbd sensor)
EMM LED 3: OFF (Cranking)
EMM LED 3: ON (Running)
Engine Monitor CHECK ENGINE display: ON
1. Switch, neutral/shift interrupt
2. Cam
008366
Stores service code 28
EMM LED 3: ON (Running)
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