Park your Yard Machine on level ground, disengage the mower deck and then turn off the mower by taking out the ignition key. This stops the blades and disables the mower from starting while you work on it.
Locate the drive pulley under the engine and pull the guide pins out of the mounting bracket for the pulley with pliers.
Grip the pulley and rotate it at the same time you pull the belt off the pulley. Rotating the pulley makes it easier to remove the belt from the pulley
Locate the tension spring on the rear left of the mower deck and then disconnect the end of the spring that attaches to the mower with a spring puller.
Pull the hairpins out of both front linkage rods and then pull the linkage rods away from the rod pins. Carefully lower the front of the deck down to the ground.
Pull the belt off the mower deck pulley system. It helps to have a diagram of the belt routing for installation. If you choose, make one before you take the belt off.
Place the new belt onto the deck and then reconnect the linkage rods. With the rods reconnected, reattach the spring to the mower.
Stretch the belt forward and place it onto the drive pulley. As you work the belt onto the pulley, manually rotate the pulley with your hand. Again, this makes placing the belt onto the pulley easier.