Mercury 525 EFI with 3.3L whipple. Left boat ramp and engine died when shifting to neutral. Restarted fine. Set alarm after getting on plane with 5 beeps and repeated every 60 secs the rest of the day. Instaled my Rhinda Diacom scanner when I got how and had history faults, CAM SNSR, and data disply showed engine RPMS at 225 rpms idling and in gear, which I'm positive it was not idling that low unless it set when engine died. Next code was IDLE MAP STR. Engine has new map sensor from whipple when having ecm reflashed at beginning of season. Another code is OVERSPEED. set while cruising at 3400 rpms. Cand get rest of data display whenI get home. Any help to understand trouble codes would be greatly appreciated.

Dustin

Best thing to do is clear the codes and run it on the hose. My guess is the cam sensor, but it could be something else.

Electronics can die at anytime, so don't put any faith into something being new at the beginning of the season.

I understand that I work in a gm dealership and see it all the time.. Is There any place to buy a new 2 bar map sensor besides from whipple?.. I also dont understand what sets an overspeed fault.

Overspeed is hitting the rev-limiter. Too small of props can do this, as well as breaking loose in rough water and not throttling back.

And will add that an overspeed fault can be set by running on the water hose (unloaded ) reving the motor past 3000 rpms or whichever rpms it is set at in the ECM program as a fault .

Never got over 4000 rpms that day. Didnt want to open it up with alarm going off. I think the overspeed code set at 3400 rpms. What does IDLE MAP STR stand for. I hate just throwing parts at anything. Thanks. I'm goin to clear the codes tonight and run it again to see what comes back.

Thanks dustin

Idle Map STR means idle RPM MAP strategy in which is the same meaning as MAP idle check in which means Sensor rationality loss of vacuum check.

next your overspeed fault can be what I said earlier throttling past 3400 RPMS on the water hose in gear or throttle only or in the water under load using the throttle only (not in gear) revving the motor at 3400 rpms or above.

Thanks BUP. That make since now. Going to retest tonight.