Mercury 350 MAG - Audio Warning System-350;377 MAG and Seacore350;377 MAG; Audio Warning System; Caution; Engine Guardian Strategy

Section 2 - Getting to Know Your Power Package
Page 46 90-8M0050539 eng MAY 2011
Audio Warning System—350/377 MAG and SeaCore350/377 MAG
Audio Warning System
IMPORTANT: The audio warning system alerts the operator that a problem has occurred. It does not protect the engine from
damage.
The Mercury MerCruiser power package may be equipped with an audio warning system. Most faults cause the warning horn
circuit to activate. How the warning horn activates depends on the severity of the problem.
There are two warning horn states:
• Caution
• Severe
Caution
If a caution state is detected, the audio warning system will sound for six one‑second intervals.
a - Horn (on or off)
b - Time (in seconds)
Below are some examples of a caution state:
• Drive oil is low (sterndrive models only)
• Sensor failure
Severe
IMPORTANT: Operators are advised to contact an authorized Mercury MerCruiser dealer if a severe fault is activated.
If a severe state is detected, the audio warning system sounds for six seconds, turns off for six seconds, and sounds for six more
seconds. Then the audio warning system sounds for two half‑second intervals every sixty seconds.
a - Horn (on or off)
b - Time (in seconds)
Below are some examples of a severe state:
• Transmission fluid temperature is too hot (inboard models only)
• Engine oil pressure is too low
• Engine temperature is too hot
• Seawater pressure is too low
• Transmission pressure is low (inboard models only)
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.
Engine Guardian Strategy
IMPORTANT: Boat speed could be reduced to idle and may not respond to the throttle.
Engine Guardian Strategy is designed to help reduce the potential for engine damage by reducing engine power when a potential
problem is sensed by the ECM. Engine Guardian monitors:
• Oil pressure
• Coolant temperature
• Seawater pressure
ON ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
1
1
1
1
1
1
1
1
1
1
1
OFF
33402
a
b
40388
a
b
ONON
6 6 6
OFF
OFF
60
½
ON
½
ON
OFF
60
½
ON
½
ON