problem with my quark 80b

[stampy]

Ive had it now for over a year and just the last 2 runs it has started acting up. it starts out fine for like the first 100ft then it slows down, and sometimes stops even with the throttle held down. then once i let off and get back on it it does it again, i cant figure it out:030: . its never thermaled or been hot enough to touch (not even close) there was nothing wrong then this happed, any body have this happen or know the cause?