The power take off (PTO) clutch in your lawnmower is the drive pulley that transfers the power of the engine to the blade. It consists of a few basic parts. The PTO clutch has a pulley that is usually machine cut and a housing brace. The pulley sits on the brace and is allowed to spin around the brace by a vertical axle in the center of the pulley.
PTO Clutch Parts
Getting in Gear
The PTO clutch is mounted under the tractor or mower beside the power drive shaft, which is also vertically aligned. It is connected to the blade shaft, and when it spins, the blade spins too. There is a belt that is attached to the drive shaft and PTO clutch pulley. The drive shaft is the main shaft connecting to the engine. When the engine is on, the shaft spins at a very high rate but the blade does not. This is because the PTO is not engaged, and the belt connecting it to the drive shaft is loose and not causing friction at its normal state.
Engaging the Clutch
To get the blade to spin, the PTO clutch must be engaged. When the operator pulls the lever and engages the clutch, the pulley wheel springs outward and tightens the blade against the drive shaft pulley. The belt causes friction and grips the pulley. Because the drive shaft pulley is turning, it spins the PTO pulley and the lawnmower blade.