Engine Guardian - Mercury MerCruiser Product Applications Manual

Tube Ref No.

Engine Guardian

IMPORTANT: The operator should be made aware that boat speed could be reduced to
idle and may not respond to throttle should Engine Guardian be called on to protect the
engine. This is covered in the Operation, Maintenance, and Warranty manual.
Mercury MerCruiser MPI models are equipped with an Engine Guardian to provide
additional protection against engine damage. The system is designed to help reduce the
potential for engine damage by reducing engine power when a potential problem is sensed.
Engine Guardian monitors:
• Oil pressure
• Coolant temperature
• Seawater pressure
• Exhaust manifold temperature (8.1S models)
• Engine overspeed
For example, if the seawater pump inlet becomes partially blocked, Engine Guardian will
reduce the available power level of the engine to help prevent damage from decreased
water flow to the engine. If the debris passes through and full water flow is restored, engine
power levels are restored to normal. In other words, Engine Guardian is a looped feedback
or smart system. Likewise, the system will reduce RPM if insufficient oil pressure or
excessive coolant temperature is experienced. Digital electronics allow the system to
monitor the oil pressure versus engine RPM to more quickly alert the operator of an
abnormal condition.
90-863758060 AUGUST 2006
Description
Liquid Neoprene
25
ALARM INDICATES LOW
OIL OR OVERHEATING
a
APPLY THE PROPER DECAL TO THE DASHBOARD
OR OTHER APPROPRIATE LOCATION:
AUDIO WARNING HORN WILL SOUND WHEN:
1. ENGINE OIL PRESSURE IS TOO LOW,
2. ENGINE WATER TEMP. IS TOO HOT, OR
3. TRANSMISSION TEMPERATURE IS TOO HOT.
TO TEST THE AUDIO WARNING HORN:
b
TURN KEY TO ON POSITION (ENGINE OFF)
a - Small decal (transparent)
Instrumentation and Controls
Where Used
Electrical connections
7637
b - Large decal
Part No.
92-25711-3
Page 9A-5