How do you replace a belt on 917.255980?

To replace the belt on a 917.255980 lawn mower, first, ensure the mower is turned off and disconnected from any power source. Remove the deck by unscrewing the necessary bolts and detaching the blade belt from the engine pulley. Install the new belt by routing it around the pulleys according to the manufacturer's diagram, then reassemble the deck and secure all fasteners. Finally, test the mower to ensure the belt is properly aligned and functioning.