The Husqvarna YTH20K46 is a riding lawn tractor with a dual-blade mower deck. The mower blades are powered by a drive belt connected to the engine crankshaft pulley. On the mower deck, you will see an idler pulley that maintains proper tension on the belt at all times. As the belt stretches, the spring-loaded idler pulley applies more tension on the belt. Due to this, there is no reason to complete routine tensioning maintenance on this mower's belt. However, there is a built-in lever that allows you to apply or release tension to the belt to engage or disengage the drive belt. This lever turns the mower blades on and off. When you disengage the drive belt, it causes enough slack in the belt to allow the belt to slip off the main drive pulley, preventing the blades from continuing to spin. Without the ability to adjust the belt tension, you could never turn off the blades, which would cause a safety risk as well as require you to replace your belt much more often.
Turn on the mower via the ignition switch located in the lower-right-hand corner of the panel just below the steering wheel.
Press the parking brake pedal located on the left side footrest. To set the parking brake, push down hard on the brake pedal.
Locate the log lever extending from the top of the control panel. It bends at a 90-degree angle as it comes out of the panel and extends to the right. On the end of the lever is a paddle handle. Rotate the level toward the steering wheel to tighten the drive belt and to engage the mower deck. Push it away from the steering wheel to loosen the tension and disengage the mower deck.