I have a weeks special powered by a us 41, the engine has been just about as dependable as it gets and pulls the 18lb weeks with power to spare. Compared to the engines of today it's heavy and gutless but for longevity I would pit it against any of today's two cycle rice burners. My US41 is over 30yrs old and has probably 1000 hrs on it and still runs like the day I got it, yep it's a junk engine.