Guardian Strategy; Audio Warning System-3.0 Tks; Testing The Audio Warning System - Mercury 3.0 MPI ECT Operation & Maintenance Manual

Section 1 - Getting to Know Your Power Package
2. Listen for the audio alarm. The alarm will sound if the system is functioning correctly.

Guardian Strategy

The MerCruiser Engine Guardian system reduces the potential for engine damage by restricting engine power when the PCM
detects a potential problem. Below are some examples of what Engine Guardian monitors:
• Oil pressure
• Engine overspeed
• Exhaust manifold temperature
IMPORTANT: Engine Guardian can reduce power anywhere from 100% to idle, depending on the severity of the problem. If
forced to idle, boat speed might not respond to throttle operation.
The PCM stores the fault for diagnostics. For example, if the water inlet becomes partially blocked, Engine Guardian reduces
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 Guardian restores engine power to normal.
Audio Warning System—3.0 TKS
Your Mercury MerCruiser power package may be equipped with an Audio Warning System. The audio warning system will not
protect the engine from damage. It is designed to warn the operator that a problem has occurred.
The audio warning system will sound with a continuous horn if one of the following occurs:
• Engine oil pressure too low
• Engine temperature too hot
• Sterndrive oil level too low
A continuous horn indicates a critical fault. Operating the engine during a critical fault can damage components. If the
warning horn emits a continuous beep, do not operate the engine unless avoiding a hazardous situation.
If the alarm sounds, stop the engine immediately. Investigate cause and correct it, if possible. If the cause cannot be
determined, contact your authorized Mercury MerCruiser dealer.

Testing The Audio Warning System

1. Turn the ignition switch to the "ON" position without cranking the engine.
2. Listen for the audio alarm. The alarm will sound if the system is functioning correctly.
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NOTICE
90-8M0113856 DECEMBER 2015
eng