replace coil and plug to be sure its not a fire problem. If that's good try a different tank. I have seen them get a hole in the cup that feeds the jet. They won't hold enough fuel for a pull under load. the engine has to have more fuel when it's under a load than when it's on the stand.
I put new gaskets on it, and a new tank. Last night was the same thing. coil and plug are next. thanks for the advice. after that, if it doesnt work im clueless.