Welcome to TBN! The only info I can add is that some of the mid-late 90's JD 425's had a Kawasaki engine with a plastic cam gear (think that's correct) of which should have been repaired by now. Careful with extrememly low hour machines - get the serial number of the tractor and the engine and you can probably find out on here via someone or a Deere dealer about it's history. Other than that, a friend of mine ran 2 of them for years in a professional capacity. He put a couple thousand hours of both of them before many repairs were required. He noted that lack of a decent Deere dealer at the time was the main reason he went to a different mower. Otherwise, he would have continued using them until he got zero-turn fever anyway.