Have 04 496 Mag that sounds like its surging at idle speed but the boat doesn't feel like it's surging. With the hatch open the engine intake sounds like heavy breathing. Is this normal?
This on a 23 footer.

It's more than likely your IAC valve doing it's job and is normal.
Has it been doing it all along or is it a new occurance?

Dave

I have a 6/2004 496 Mag base and it surges at idle with the hatch open as well, I always wondered about that.

Yea it's always done it. I don't really notice it unless the hatch is open. Tach seems not to move in relation to the surging.