98 gp 800 rebuilt motor, put in water would run but not go past 5500 and died out, rebuilt carbs and added another inline fuel filter, ran great for half an hour, then the same thing wont go past 5500 and dies, i cant see the carbs needing to be rebuilt again, it seems to run a little better out of the water, same with before the carb rebuilds, im all but lost at this point any suggestions / similar problems