The alarm could be anything...just because you changed the impeller does not mean thats where the alarm is coming from. Before throwing money at things, have it scanned to see what really is going on.

I got ya , Going to River on 8-25 gonna see what happens.
You know the funny part is that it only does it when I first start the boat and it has a chance to start warming up.
Once alarm goes off I put it in gear its gone for the rest of the day.
Ill keep you posted thanks for the help....