ime not shaw its the rings, we seem to have lots of compression ime realy stumped now, we have done the points, tried 3 carbs, 4 spark plugs, reground the valves in, changed the needle hights and it still will only run on choke for about a minute before it stops, this is the first small engine that i have ever come across in my life that me or some one around me could not get going :banghead: :banghead: