You will need: 4 cycle engine oil, a plastic pan to dump the old oil into, a grindstone bit made just for mowers, an electric drill, a vise, a socket wrench, a large flathead screw driver and safety glasses or goggles.

Pull the mower onto a hard flat surface such as a driveway or level patio.

Unscrew the spark plug with the socket wrench. Always remove the spark plug before doing any work below the deck! Removing the spark plug will prevent any chance of the mower accidentally starting while you are working on it.

Look at the end of the spark plug that has been inside the engine and inspect it for signs of corrosion. If there is none, you do not need a new spark plug and can put it back into the engine when finished with the maintenance. If the spark plug is corroded, you will need a replacement.

Unscrew the cap on the oil chamber. It will usually be on the opposite side of the engine from where the gas cap is. (If yours is on the same side as where the gas goes in, you'll have to drain your oil from underneath the deck.) There should be a short dip stick attached to the underside of the cap. Turn the mower over slowly so that the old oil drains out into the plastic pan. Be sure to dispose of the old oil properly at a landfill or service station. Never dump it on the ground or down a household drain!

While the oil is still draining into the pan, use the socket wrench and take off the nut and washer securing the blade arm of the mower. Put those in a cup where you'll be able to find them again, and then remove the blade arm itself. Clean any caked on grass off of the underside of the deck.

There are 2 blades, one at each end of the blade arm. Sharpen them one at a time. Place the blade arm into the vise of your workbench. Put the grindstone bit into the drill. Always wear safety glasses or goggles when grinding!

Begin to sharpen the first blade. Shine up the bevel of metal on top of the blade with the bottom of the grindstone. Then flip over the blade arm, securing it in the vise again and run the length of the blade between the grindstone and the white plastic guide attached to the upper end of the bit. Alternate back and forth between the two surfaces, flipping the blade arm as needed, until the blade is sharp. Then do the same thing to the blade on the opposite end of the blade arm.

Put the freshly sharpened blade arm back onto the underside of the deck, securing it with the washer and nut. Gently tighten the nut. Use a large flathead screw driver and unscrew the cover of the air filter compartment. Remove the sponge-like air filter. It contains a small amount of engine oil and will be fairly dirty. Wash it in a pan of water with a small amount of soap and degreaser. It is best to dispose of the dirty water at an approved facility so that the engine oil in the filter does not enter the sewer or storm drain systems. You do not need to replace the air filter unless it is disintegrating.

Put about a tablespoon of the new engine oil on the air filter and work it in with your fingers. Put the filter back in its basket and back into its compartment, screwing the cover down tightly, but not too tight.

Put the new engine oil into the oil chamber. Some engine oil comes in a bottle containing more oil than what will fit into the engine, so be careful and do it slowly. Keep checking the level with the dipstick attached to the cap every couple of teaspoons until the proper level is reached.

Lastly, put the spark plug back in with the socket wrench.

Fill the gas tank with new gas and start the mower.