Section 2 - Getting to Know Your Power Package
90-8M0074352
eng
OCTOBER 2012
Page 37
The MerCathode has a 5‑amp fuse that connects to the positive (+) terminal on the controller. If the fuse is open, the system
will not operate, resulting in a loss of corrosion protection.
a -
MerCathode
b -
Red/purple wire
c -
5‑amp fuse
Audio Warning System
The 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 (if equipped with a drive reservoir having low oil level switch)
•
Transmission temperature is too hot (if equipped)
NOTICE
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.
Guardian Strategy
Engine Guardian 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: 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, 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, Guardian restores engine power to normal. To avoid recurrence of the problem, contact
an authorized Mercury MerCruiser dealer.
a
c
50534
b
