I dont think you need to go back to factory settings I think you need to richen the lsn about 1/8 and try again. go back thru this thread and read what mine was doing when I first got one see if that is similiar to what your prob is. I just had to keep it rich and blowing tons of smoke and it ran great then after about a gallon of fuel it quit smoking as much and really started to haul a$$ . also there are factory needle settings in this thread somewhere.