MerCruiser Scorpion 350, User Manual

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Section 2 - Getting to Know Your Power Package
Page 28 90-899883175 DECEMBER 2007
If a severe fault is detected, the audio warning system will sound for six seconds, turn off
for six seconds, then sound for six more seconds.
33403
a
ON ON
6 6 6
OFF
b
a - Horn (on or off)
b - Time (in seconds)
Below are some examples of a severe fault:
• Engine oil pressure is too low
• Engine temperature is too hot
• Seawater pressure is too low
• Transmission pressure is low (select models)
OBDM
If an OBDM fault is detected, the audio warning system sound with one five‑second horn,
then one short, 1/2‑second horn every 60 seconds for certain faults related to the emissions
or fuel system. See your authorized Mercury MerCruiser dealer for assistance.
33404
a
OFF
ON
5 60 60 60
½ ½ ½
ON ON ON
OFF OFF
b
a - Horn (on or off)
b - Time (in seconds)
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.