Mine did the same thing, it had sat for 2 years. it also had sat with almost no gas in it... after 2 tanks of gas and 2 cans of Berrymans (my personal favorate) and a pair of new filters, I ran it low on gas, put a 5 gal. can under the drain with a paint strainer and drained the tank. then took the line off comeing to the filter with the cap loosend and used short blasts of air (wach the pressure!) I couldn't believe how much varnish I got out. it came out like snot the dried in the filter. it was enought to float around and restrict the tube that feeds the pump. the cleaner probably would have desolved it eventually, but this really seemed to take care of mine. It just dropped the fuel pressure enough that it couldn't keep up in the upper gears. Works great now. good luck!