Warning: .26 = POS DO not buy!!
By chance do you run a filter on it? Ive had the same problems as you, and come to find out the fuel filter was messed up, the o-ring had pretty much self destructed and in order to get the tight fit, I had smashed the end of the filter element, thus causeing the engine to run unconsistantly and over heat. After I replaced the o-ring all was slightly fixed and power increased, but still had problems, then I just put a new filter on and bamn the engine came alive with a little tuning!! No problems since the change!!
Now this was my expierience(sp) so I just thought Id give you something to think about!!