My father in law bought on e from an auction last week. It was the same and would start when primed but would stop when load was applied. I fixed this by taking the carb apart and the fast or main jet had jelly/sludge like stuff blocking it. I cleared the blockage and cleaned the rest of carb. This was obviously why the machine was in the auction for sale. It now runs really well. Hope this helps.
nigel jordan
April 2008