I have a case 430, it was running great then all of a sudden it started missing yet sometimes I could choke it and it would be OK. Other times it didn't seem to help. I did run it out of gas and added one gallon I had on hand, after that is when it started acting up. The gas I added was unleaded but was OK. I put in new points, condenser and a new coil, no help. Anyone have any idea as to what could be causing the problem. Is it possible that the ignition switch is bad. Also one time when I went to start it, there was no spark at the point but as I moved the screw driver near the points I got a spark away from the points and then I had a spark at the points.