Hi can anyone help me with some troubleshooting on my yamaha 150 two stroke.I am unable to obtain more than 4600 rpm out of the engine. I have had the engine serviced , carbs and jets cleaned .All cylinders are firing as the pots are hot .New rako fuel filter installed , and am runing the engine off a seperat caddy tank , water free.The prop is the same prop used when the engine obtained 5800 rpm before.My maintinance facility say i might have water in the hull , but with two men on the boat ( 19.5 foot) it gets on the plane at 2400 rpm , so i have my doubts about that.When i power up the engine is running smoothe , i obtain 4600 rpm wit 3/4 throttle but when i move to full throttle the engine sits at 4600 rpm.Any help would be appreciated.