I have 2007 mercruiser 496ho, when i accelerate to 3000rpm the engine sound constant beep and loss power if i keep it down to 1200rpm beep go away, i check my water temp is 170, oil pressure is 25psi. does anyone have this exper. thank you

It is going into gardian mode. You need a scanner to check for sure. Impeller, exhaust sensors? You just dont know without one.

Drive lube resevoir low? Water pressure sensor (bad impeller).

Hi Daytona i have twin 2001 496 HO in 28foot pantera can you tell me where best to buy the scanner i would need .no ploblems as yet but like to be ready. thanks for any help you can give me regards paul

http://www.rinda.com/marine/marine.htm

Thats the one I have. If you start having problems, you can get your own codes and someone here on the boards can help you. It has worked for me more than once.
Good luck Mitch