8.1L Crusader Check Engine Light and Alarm

[rcwiegand]

Running in at 3200 rpm after fishing for six hours when check engine light and alarm went off on starboard engine.  All gauges were fine, slowed to idle and finally turned ignition off and restarted to stop the alarm.  Started up and ran to 3200 and alarm and check engine light went off again after a minute or two.  Stopped, restarted engine to stop alarm and ran in at 1800 for six miles, no alarm or check engine light.  Have a mechanic coming to read trouble codes, we were planning an extended trip starting next week and hope this is not a major issue.  Any ideas what this may be or what to expect?  The boat is a 2004 35 Open with 1600 hours-mostly idling hours.

[wallyman424]

Running in at 3200 rpm after fishing for six hours when check engine light and alarm went off on starboard engine.  All gauges were fine, slowed to idle and finally turned ignition off and restarted to stop the alarm.  Started up and ran to 3200 and alarm and check engine light went off again after a minute or two.  Stopped, restarted engine to stop alarm and ran in at 1800 for six miles, no alarm or check engine light.  Have a mechanic coming to read trouble codes, we were planning an extended trip starting next week and hope this is not a major issue.  Any ideas what this may be or what to expect?  The boat is a 2004 35 Open with 1600 hours-mostly idling hours.

My moneys on a misfire. Likely a coil pack or spark plug. Otherwise it's possibly just a sensor gone wacky. 

As long as the motor was running fine without any odd noises, exhaust smoke or loss of power it's going to be something easy.

[Medicone]

I vote faulty cam shaft sensor.

Had a similar problem on my 2003 35' Open w/8.1 Crusaders.  Alarm would go off around 3100 RPMs, ironically, also on the starboard engine.  No problems below 3100 RPMs.  Nothing sounds worse than that buzzer when on a trip.

Code reader indicated cam shaft sensor.  Replaced the sensors on both engines, relatively inexpensive, and have not had a problem since (3-4 years ago).

[rcwiegand]

It was the crankshaft sensor.