Mower blades inevitably become worn and dull from use. When mower blades are no longer sharp and in top condition, they do not cut the grass well. Instead of shearing the grass off cleanly, they rip and tear at the grass blades. This results in grass blades getting ripped completely out of the ground or getting shredded. Improperly cut grass can provide an entry point for fungus and disease which may harm or kill the grass. Preventing these problems is easy; all you need are a few simple hand tools to install mower blades.
Remove the gas from the gas tank of the lawn mower. This can be done simply by letting the lawn mower run until it's out of gas, or by siphoning the gas into a gas can.
Disconnect the spark plug cable from the lawn mower so that the lawn mower can't start up while you are installing the mower blade.
Lay the lawn mower on its side. Hold the blade in place by wedging a two by four board between the blade and the mower deck.
Remove the lawn mower blade. The lawn mower blade is held to the engine shaft with a single bolt through the middle. Remove this bolt and set aside any washers that come off along with the blade.
Take the new blade and install it by replacing the bolt and any needed washers. Tighten down with your adjustable wrench.
Set the mower back upright and fill the tank with gas. Your lawn mower is now ready to cut grass again with a new, sharp blade.