My tractor has been sitting for a couple of years and I got the urge to take a look at it. When it quit I thought it had a solid state ign issue. When I started looking into the problem the ign switch ground had fallen off, I put gas in it and temporarily attached the ground and it started right up. Then I aired the tires, changed oil, jumped it again and drove it around for 45 min. Ran fine, so I figured I would spring for a battery. I was feeling pretty good until I went to start it after replacing the battery and it made a putt and stopped. The spark was there for a few revs and then it ceased to exist. Naturally, it will not start. If I wait awhile it usually it will start. Any ideas? I went out later that evening and it started up and ran fine. I tested for spark and it was there every time (?) Then the spark disappears and back to waiting till the spark returns.