My ztr today started dying on me when doing my own lawn. I would let it sit for 5 minutes and it would then start up okay. It then died again after about 10 minutes. It did did this a few times. I checked a few things like air filter,etc but still had the problem. I then cleared out the deck of all the grass and lots of thick packed in grass under the seat area near motor, hydros and back wheels. The ztr is working okay now so I assume the buildup of grass caused something to overheat and shut the ztr down until it cooled down. You just never know what a buildup of thick old grass will do to your mower.