Dick, Funny you should mention this. I have a 70's Vintage Homelite super XL. A nice built saw. I love to use it when working tree's in the 12"-20" range. Mine had a similar problem an it turned out that the needle and seat had gunk in it. Sometimes it would stick shut, other times stick open. Either way it would kill the engine. I took it apart and cleaned it and no problems for the past few years.