I had a similar issue with my machine (it's a real shame that the oil drain tubes don't all have flats to put a wrench on). I used vise grips, but tried to grab some of the exposed threads and kept adjusting the vise grips until I could just get them closed onto the oil drain pipe. This spring I'm converting the oil fill tube to a flexible hose that Briggs & Stratton sells (p/n 1723165SM).Tried back and forth, held with vice channel locks and used impact drill. No good, tube spinning. Cleaned exposed threads, applied liquid wrench, letting soak. Anything else??