Tough question to answer as it depends mainly on how it has been taken care of. I've seen a twisted crank on a Yamaha 1200 with 8 hours on it, a SeaDoo GTI LE RFI blown up with only 18 hours, and a four month old GTX 4-Tech blown up with 22 hours on it. On the other hand I've seen numerous pwc's with over 200 hours running strong. So far the one with the most hours and still running was a 97 GTX with 415 hours, it looks like hell and the motor has the SeaDoo death rattle but the owner says he'll run it til she blows up!!!