I have an American Yard Products riding mower, model 4180-54, that I need the mower deck belt diagram in order to replace a broken belt.

This site may be helpful in getting you a picture. AmericanYardProducts.com | American Yard Products | Yard Spray | American Yard Products Lawn Mowers | Yard Plant (http://www.americanyardproducts.com/) The mower deck has at least one more pulley than you have blades. IE a three blade deck will have at least 4-5 pulleys and one is a sopring loaded tensioner. Put you new belt around the 3 blade pulleys and the drive pulley from the engine. Pull the tension back as much as you can with the blades disengaged, it should go on. Look on the deck or under the foot rest, frequently a decal will be found showing the belts.