Mercury 300R HD CMS Mechanical Operation And Maintenance Manual page 39

FEATURES AND CONTROLS
1. Continuous six second beep: Indicates a critical engine condition.
Depending on the condition, the Engine Guardian system may engage
and protect the engine by limiting power. You should return to port
immediately and contact your servicing dealer.
2. Intermittent short beeps for six seconds: Indicates a noncritical engine
condition. This condition does not require immediate attention. You may
continue using your boat, however, depending on the nature of the
problem, the engine's power may be limited by the Engine Guardian
system. Refer to Engine Guardian System. You should contact your
servicing dealer at your earliest convenience.
It is important to note that in either of the above scenarios, the horn will only
sound one time. If you key the engine off and restart it, the horn will sound
again, one time, if the fault is still present. For visual display of the specific
engine functions and additional engine data, refer to SmartCraft Product
information, following.
A few of the noncritical conditions indicated by the intermittent short beeps for
six seconds can be corrected by the operator. These operator correctable
conditions are as follows:
• Water in the engine mounted fuel filter. Refer to Maintenance ‑
Low‑Pressure Fuel Filter.
• Cooling system (water pressure or engine temperature) problem. Stop the
engine and check the water intake holes in the lower unit for obstruction.
• Low engine oil level. Refer to Fuel and Oil ‑ Checking and Adding
Engine Oil.
ENGINE GUARDIAN SYSTEM
The Engine Guardian system monitors the critical sensors on the engine for
any early indications of problems. Engine Guardian is functional whenever your
engine is operating, so you never have to be concerned about whether or not
you are protected. The system will respond to a problem by sounding the
warning horn for six seconds and/or reducing engine power in order to provide
engine protection.
If Engine Guardian has been activated, reduce the engine speed. The problem
will need to be identified and corrected. The system must be reset before the
engine will operate at higher speeds. Moving the throttle lever back to the idle
position will reset the Engine Guardian system. If the Engine Guardian system
has determined the reset has not corrected the problem, Engine Guardian will
remain activated, limiting the throttle. The problem must be identified and
corrected before Engine Guardian will allow the engine to reach a normal
operating RPM.
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