I had a problem with mine when I would go over 30000 RPM's in drive, the beeper would go off. After a lot of checking and $300 to the boat shop it turned out to be the switch on the shifter lever was not making a good contact. My on board computer thought the boat was in neutral and it was warning me I was going to over rev the engine. The switch looked fine we pushed it in another 1/32 of an inch and it solved the problem. Just a thought, you might check your shifter lever switch.