I bought a Cub Cadet 1042 last year and recently it's been running rough, skipping and eventually shutting down. It runs great when I first start it but after making a couple of laps, the problems start. I can let it sit for a few minutes then it will run great again for a couple more laps then shuts down again. I've replaced the air filter, fuel filter and spark plug but that hasn't solved the problem. The gas I put in it was good but it runs like there's water in the gas and, like I said, if I let it cool off, it runs great for a while. Anybody have a suggestion of what might be causing this?