04' 90 Horse 2 Stroke Yamaha bogging down

Hello,

I am having an issue where my 04' 90 Horse 2 Stroke will start up and idle fine, it will run at full power (5000 RPM) then after a little while while in gear will bog down to about 2500 RPM at full throttle. It will even run fine for sometimes up to 30 minutes before this will occur. So far I have had the carb's rebuilt, replaced every fuel line, the fuel/water seperater, the fuel tank and rebuilt the fuel pump (replaced diaphram and gasket). Today while I took it out and ran it for about 30 minutes and it ran fine in gear, when I dropped it into neutral there was a lot of white smoke coming out of the exhaust. I did not run it for a few hours, then tried running it a gain and the same issue occurred where it bogged right down.

Any thoughts on what can be causing this?

Thanks

Al

White smoke (which is actually steam) is a sign of water in the combustion chamber. How it got there is the question. It could be from the fuel tank - or it could be from the cooling system. Obviously the easier check is the fuel system. But, you'd be seeing it all the time if it were the fuel...

Thanks-
This was the first time i took it out since replacing the tank and the lines and it was a fresh tank of gas in there so I am thinking it is the exhaust..... Any thought on how/where the water may be coming in through the exhaust? Manifold possibly?