Originally Posted by davidpm
It is fresh water cooled.
But the fuel idea is interesting. He did replace the fuel pump recently. I guess if something is blocking the fuel even with the throttle working perfectly it would still cause the rpm's to be low with no lugging.
We did remove the fuel tank and clean it etc at the beginning of the season.
But he did have fuel issues for the last couple of years.
I'm pretty sure I know when the problem will be duplicated. At the worst possible moment.
FWC as in it has a heat exchanger?
If the main jet in the carb gets blocked temporarily you will just have idle speeds available. If you have the Zenith carb you can remove the 1/2" main passage plug that drains the gas out of the carb. Catch the fuel in a clean container and look for crud; even small specks can cause problems.
Good thing you cleaned the fuel tank. They can get really nasty if left for years...
Worst possible moment is always when you will find it again. Were the fuel lines replaced as well? They can corrode from the inside because of the Ethanol in the gas. Your tax dollars at work!
Pic is what was at the bottom of our fuel tank.