There are a number of reasons why you may need to remove the mower deck from a riding lawn mower. You need to remove it to replace the drive belt or to put on new cutting blades. Because the mower deck is a rather large piece of a riding lawn mower, it can seem a bit daunting to take it off, however, the job is not as complicated as it seems and can be done in a relatively short period of time. All you'll need is a pair of pliers and maybe a wrench.
Drive the riding lawn mower to a flat working area. Turn off the engine and engage the parking brake. Disengage the blade rotation using the blade rotation control. Put the lift lever into the leveling position and release the tension on the drive belt.
Locate the hairpins on either side of the adjuster arms. Use a pair of pliers to pull both pins out, removing the washers as well. Locate the pins on either side of the lifter assembly and pull them out.
Pull the extension spring out of the hole in which it rests, in the blade control rod. Remove the hanger rod from the front hanger. On some models you may need to remove a couple carriage bolts to get the rod out. Lift the drive belt over and off the stock pulley. This is the pulley located nearest the two back tires.
Remove the mower deck from the right side of the riding lawn mower. Loop the belt back over the stock pulley. Place the lift lever into the top position. It is now safe to drive the riding lawn mower.