Got the 121 out today with the Bush Hog Flail mower. Grass was wet and I didn't feel like plugging up the deck on the 1641. Took the muffler off the Power Horse engine, flipped it around so now the exhaust blows out the back instead of at my head. Also removed all the pollution crap on it. It used to run good for 10-15 minutes and then it would shut off from lack of gas to the carb. made me nuts until I realized that it had a spring loaded check valve built into the gas cap. No way it could get air into the tank. Spring and valve no reside in the trash can, problem solved.