2002 175 EFI OVER SPEED ALARM @3700 rpms?????

[BV74]

2002 Mercury 175 EFI-L, #OT445648 #1175413ZD....

Here’s a little background on the motor. Blew #3, fresh rebuild... Dropped in the lake would idle great, try and get on plane and get a solid alarm (over heat). Did that a couple times. Replaced t-stats. Still did it. Brought it right back to the shop. They pulled heads, and water in the block. Head gasket gone. Replaced all the gaskets including water pump. Fixed that issue, but now oil alarm! Replaced sensor. Fixed that problem.. ran the boat around for a little bit. Now getting over speed alarm @3700 rpms and goes right into guardian mode. It’s like it spun a prop hub. What would cause this motor to hi an over speed alarm @ 3700????? when I believe it’s high limit is 6150. I was thinking maybe stator?. I’m lost right now... Any help would be GREATLY APPRECIATED. Thanks in advance for any and all help!

[leonreno]

I’m not fully sure, but You may be able to get an over speed alarm in neutral or if maybe if the tilt is to high. If you are getting these alarms while running in gear, could be a faulty gear position sensor. But I’m not 100% sure that is possible.

[BV74]

Thanks a lot for the input. Yes, getting the over speed alarm while in gear. It just kills me. The motor ran great. Never any issues, until the #3 cylinder decided to eat a ring. I have a total rebuild done. Now I’m getting all sorts of different alarms. Fix one and another pops up.... I don’t know if the throttle position sensor would show on the reader or not. Thanks again.