Re: Wont rev over 2000 rpms when in the water?
That's a tower of power I6. On muffs, you don't need any fuel to speak of as you are doing no work...HP is energy expended. Prop turning air, no energy expended. On the water you need BTUs to roll the prop against the water resistance. That means that you need fuel availability that you didn't get on muffs.
Two things come to mind: Timing issues, or fuel supply issues. Having had the year later model of that engine, and having run it out of gas at WOT I will be inclined to fuel, but.....
First of all what is the history of the engine, where did you get it, when, what was done to it, what did you do to it besides what you stated since you acquired it, how long ago did you acquire it, how did it perform when you bought it, what kind of rig are you running it on, what kind of fuel supply system do you have, have you checked the linkages to ensure that the spark continues to advance after the carb butterflies are fully opened, what kind of and pitch prop are you running, does the squeeze bulb collapse when trying to run above 1800, does squeezing the bulb above 1800 improve performance?
Do your homework and come back for help.
Mark