It sounds like the drive belt has slipped off a pulley. With fuel turned off, tilt the mower to one side- so the fuel cap is at the highest point of the tank, and cannot leak fuel out the breather hole. One belt will drive from the engine and the other end goes around an idler pulley. The other belt will drive from the axle to an idler pulley and will be slightly loose. This is the one that may have slipped from its position and not be contacting one or more pulleys when tightened. There should be a pair of pulleys, each being one side of the drive belt. Pressing the forward control should move one pulley onto the drive belt and simultaneously tighten the axle belt. Pressing the reverse control should engage the other pulley(on the opposite side of the belt) and also tighten the axle belt. This loose belt may have been bumped off one or more pulleys in the collision, and be sitting between the pulley and the guide/guard. With the ENGINE OFF, and the forward/reverse selector in neutral you should be able to force the loose belt back over the pulley. Whether the forward/reverse mechanism drives the engine or axle pulley, the principle will be the same.
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It sounds like the drive belt has slipped off a pulley. With fuel turned off, tilt the mower to one side- so the fuel cap is at the highest point of the tank, and cannot leak fuel out the breather hole. One belt will drive from the engine and the other end goes around an idler pulley. The other belt will drive from the axle to an idler pulley and will be slightly loose. This is the one that may have slipped from its position and not be contacting one or more pulleys when tightened. There should be a pair of pulleys, each being one side of the drive belt. Pressing the forward control should move one pulley onto the drive belt and simultaneously tighten the axle belt. Pressing the reverse control should engage the other pulley(on the opposite side of the belt) and also tighten the axle belt. This loose belt may have been bumped off one or more pulleys in the collision, and be sitting between the pulley and the guide/guard. With the ENGINE OFF, and the forward/reverse selector in neutral you should be able to force the loose belt back over the pulley.
Whether the forward/reverse mechanism drives the engine or axle pulley, the principle will be the same.