I recently bought an older L2850 w/1700 hours and don't have any history for the tractor. Everything looks relatively original though. After an oil change, air filter cleaning and new battery I used the tractor without any problems for about 4 hours. The next day I used it for 6 hours or so mowing and started noticing the tractor was losing power when under load situations, i.e. heavier mowing conditions, uphill, etc., to the point I would need to stop and let it catch up. At times it seemed it wouldn't have power enough to make it back to the garage. Then it would recover and seem to run ok. It was doing this very frequently to the point I stopped mowing. Being a new Kubota owner, I really don't know where to start diagnosing the problem. Operating temperature was normal. I thought about possibly a fuel filter problem and will check that. I realize this is not a lot of info to go by, but any thoughts or ideas from others who may have experienced similar issues, would be appreciated.