Sharpen a mulching blade by preparing the mower for blade removal, removing the blade, filing the blade, and checking for balance. Once the blade is sharp, reinstall it on the mower.
- Prepare the mower for blade removal
Disconnect the spark plug wire. Drain the gasoline from the tank into an approved storage container, and then tip the mower on its side to access the blade. Wedge a small block of wood between the blade and the mower deck to immobilize the blade for removal. Mark the bottom of the blade, using spray paint.
- Remove the blade
Use a socket and driver to remove the retaining nut that holds the blade in place. Remove the blade from the mower.
- File the blade
Place the blade in a vice, and tighten. Use a file to sharpen the edge of the blade, including the area along the mulching curve. Reverse the blade, and follow the same procedure for the second end.
- Check for balance
Place the mounting hole over a nail driven into a wall to check for balance. If one end drops, file that end some more to balance the blade. Continue checking and filing until the blade remains horizontal on the nail.
- Reinstall the blade
Place the blade back on the shaft, and insert the bolt. Tighten the bolt with the socket wrench. Turn the mower upright, and reattach the spark plug wire.