Hello! I am looking at an old Gravely, model 810 (as stated on the hood). It starts, runs and moves, but the PTO does not engage. All the tires hold air, and it looks to be in decent shape. It has a mower deck and a 2-stage snow blower. The serial number is 00295461. Are there parts available for this thing? What is the horsepower of the Kohler engine? Any clue what a fair price might be for this thing? Any advice you can give me? Thanks.