2002 Mercury 50 hp 4 stroke with 4 carburetors, stutters , bogs, loses power surge at 3300 rpm. The motor runs fine at lower rpm. Starts easily. The gas is fresh, filters clean and fuel pump is fine. New plugs installed and after a 3 hour run they appear blackened and a little damp. I think it might be a timing issue? It's just strange how it runs perfectly up until 3300 then like clockwork just before the boat is on plane it seems to lose it's power band. Wide open throttle is about 5000 but should be 5800. The motor has a new prop that is appropriate for the boat. Any thoughts would be greatly appreciated.
Jim
Jim