For the first and second year that I owned my B3030 it would sometimes, after mowing for at least an hour, develop a catch in the movement of the HST pedal that prevented full speed. The immediate fix was to lift my foot off of the pedal and then press it down again. It would work fine for a while and then the same problem would reoccur randomly. I could never find any thing obstructing the movement of the linkage. I suspected that the pedal buffer was the cause, but never had the problem again after the second mowing season. It has worked perfect since and now has about 422 hours on the clock. I still don,t know why it did it. It only happened when I was in medium range as well, but I don,t think that had anything to do with it. Good luck.