There is a lever that acts as a tension release on the right side top of the deck... it is toward the back of the deck, and has a hefty spring attached to it, going toward the center of the deck.
This lever should be turned counter clockwise so that the semi-circle cut out in the metal lever cups around the spring. That return tension to the spring, thereby keeping a nice tight drive belt to the engine. Without this tension, the belt may turn some, but can't cut without slowing or stopping. If the tension arm is all the way released, you may see the spring dangling from the rear of the deck. This allows you to remove the belt for replacement.
Jared Hendrickson, August 2007
