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Michael, Master Mechanic
Category: Boat
Satisfied Customers: 257
Experience:  Over 25 years experience working on everything from PWC's to Mega Yachts
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I have a 2005 Mercruiser Magnum MPI with the SmartCraft

Customer Question

I have a 2005 Mercruiser Magnum MPI with the SmartCraft system. I get a continuous engine alarm when throttling up above 1500-2000 RPM. Alarm goes of when throttle reduced to idle. All dash gauges have normal readings. Problem was intermittent but now happens most of the time. Any thoughts?
Submitted: 2 years ago.
Category: Boat
Customer: replied 2 years ago.
MAG 350 Bravo III. All fluid reservoirs at normal fill line. Had a tech onboard during a Sea Trial with Sierra diagnostic computer. No codes showing when engine alarm goes off and protection mode activates.
Expert:  Michael replied 2 years ago.

Hi, my name is Mike,

Since the engine is not throwing any fault codes its likely to be something simple..

Try this.... find the temp sensor on the transmission cooler (heat exchanger) and unplug it while the alarm is sounding, if it silences it you have a bad sensor/switch.

Let me know what you find and we'll take it from there.