I have a 2001 vmax 225 with new water pump 2 years ago. Recently a warning buzzer came on while going no wake. I shut down engine, and buzzer sounded again when key turned on but boat not started. Funny thing is when started and engine revved buzzer stopped. While moving on plane buzzer did not sound but when going through no wake zone came on again. New plugs, water gauge shows pressure, new oil. Any thoughts?