My 425 seem to be doing something similar. Today, after about an hour mowing, and then heading back to the shed, it abruptly quit. No sputtering, no warning, just quit. Trying to restart did not produce even a pop. I could hear the fuel pump running every time I tried to restart. After about 5 minutes of trying to restart, I started to get a pop or two. After a couple more minutes, more consistent popping. Then after a few more minutes of trying to restart, it popped and sputtered, and then began running again, as though nothing had happened. This is the third time this has happened. And curiously, the tractor always has died in the same spot in my back yard on the way to the shed! Maybe my back yard is haunted? I suppose something must be overheating, but I can't imagine what. Does anyone have any ideas? Or suggestions as to how to troubleshoot?