I've got a Toro Wheel Horse manufactured around 1991, with a 3 blade detachable deck. There are 3 belts.. the drive belt, the belt that runs from the clutch/PTO to the deck (which drives the blades) and the belt that runs all 3 blades. The belt that runs the blades keeps getting chewed up. A new belt will last one session of mowing. The next time I try to mow, the belt will twist, and slip off, eventually getting chewed up in the process. I've cleaned the deck and sharpened the blades, which are about 2 seasons old. It hasn't helped. Each blade has its own pulley on the top portion of the deck that the belt runs around, and I have noticed that the center pulley seems to spin off-center a little. I'm wondering if this pulley needs to be replaced, or if there could be something wrong in the tensioner spring assembly. The assembly seems to be adjusted by loosening a bolt and moving the bar and spring up and down the deck. I have it set about mid-way. Anyone familiar with this mower? I'd appreciate any insight! I'm getting tired of replacing belts... Thanks!