I just have to relate this story. My wife, as is her wont, was mowing while I was out of town for the week. When I called to let her know that I had arrived, she told me the John Deere rider had stopped after about 15 minutes and she had to get the neighbors to help push it back to the house. From her description, we agreed that it was either a fuel or air problem. Several times over the week I looked up solutions and accepted that my return-home-obligations would circumvent my return-home-festivities. I arrived home, my wife reminding me that the grass was growing, and I again checked the Internet for troubleshooting. As usual, I was expecting the worst. I headed out to the garage intending to check the gas cap vent first. Vent was fine. Gas tank was fully intact. How did I know? There was no gas in it. Bone dry. Filling the tank had an amazing effect. The tractor ran perfectly. My wife continued her mowing. And, I got my nap. Never rule out the simplest explanation. Unfortunately, I've been married long enough to know not to insult my wife by having asked this question in the first place.