1. Disconnect the spark plug wire. This is important to prevent the mower from starting accidentally while you are working on it.
2. Remove the nuts and washers that hold the blade. There are usually two nuts and washers on each side of the blade.
3. Pull the blade up and off of the spindle. You may need to use a pry bar or hammer to loosen the blade if it is stuck.
4. Inspect the blade. Look for any damage, such as cracks or chips. If the blade is damaged, it should be replaced.
5. Sharpen the blade. If the blade is not damaged, you can sharpen it using a file or sharpening stone.
6. Reinstall the blade. Position the blade on the spindle so that the cutting edge is facing downward. Put the washers and nuts back onto the spindle and tighten them securely.
7. Reconnect the spark plug wire. Make sure that the plug wire is secure.
