I purchased a Scag Turf tiger in late 1999. This machine has the 25hp Kohler horizontal engine and a 61" standard cutting deck. I put on about 50hrs this season and had only two problems. 1. The engine will diesl(knock)when shut down if it is running at idle. I was told by the dealer to run the engine at 1/2 throttle and then shut down. 2. There is an intermittent hesitation when the machine is started. The key is turned on but nothing happens. I have to hold the key on the on position and then the started engages. Other than these problems, this machine seems to be very rugged and performs well. After reading some posts on this board, I called the dealer and was told that the pre 1999 STT mowers were problem prone and that this was corrected in 1999. What has your expierence been with these 1999 machines? I am trying to identify any potential problems before the warrenty runs out. Thanks, Rich.