If your yard has an uneven or ragged cut after you've been over it once with your zero-turn radius lawnmower, that likely means it's time to change the mower's blades. Before every use, check the blades on your mower to see whether they have become dull or nicked. Heavy use can cause blades to deteriorate. You can also damage blades in various ways, including running over a thick branch. When it's time to change the blades, leave yourself about 20 minutes for a task that most people can do.
Pull the spark plug wire to prevent the mower from starting while you are servicing it. Position two hydraulic jacks at the front of the mower and lift it high enough to gain access beneath the mower deck. Place the mower on jack stands once you have reached the desired height.
Put on work gloves to protect your hands from being cut while working around the blades. Place a 2 by 4 block of wood between the blade and mower deck to prevent the blade from rotating while you service it. Use an electric impact wrench with a six-point socket to loosen the blade bolt. Remove the bolt, washer, blade and blade spacer.
Insert the blade bolt through the washer, blade and blade spacer. Check to see that the beveled cutting edge is on top of the blade. Place the blade assembly on the blade spindle and tighten with a torque wrench to 70 ft. lbs. or the precise torque recommended in your owner's manual.
Repeat the removal and installation process for your mower's other blades. Use the hydraulic jacks to elevate the mower enough so you can remove the jack stands. Lower the hydraulic jacks. Reattach the spark plug wire.