VMAX Series 2 200 Idles rough and wont exceed 3500 RPM under Load!

[johnniebgood]

Engine idles like it is not firing on all cylinders. Very rough at low idle under load. Will not exceed 3500 RPM which will barely put my Hewes on plane. Ran boat all week without any problems. Using Ethonal free gasoline. Only 53 hours on engine. No warning sensors went off. What could be my problem?

[boats.net]

Run a compression test, run fuel pressure and vacumn test, check fuel pumps.