The spark plug can usually be disconnected by removing a prominent wire on the side or front of the lawnmower engine from its metal mounting. Once disconnected, the engine should not be able to start. For safety purposes, it’s still recommended to wear heavy gloves and eye protection during this project even if you’re sure you’ve disconnected the spark plug.
The carburetor and air filter on most modern mowers are usually housed in a boxy plastic case on the side of the engine. If you’re unsure of where these parts are located on your mower, consult your owner’s manual or contact your manufacturer. As additional protection against spilling, you can run the mower until it’s out of gas, or pour the oil into a separate container. This project is also a good opportunity to check your oil and change it if necessary. It’s a good idea to change your oil at least once a year.
There are many ways to do this. For instance, you may want to mark the bottom of the blade with a dot of spray paint, inscribe your initials with a grease pen, or simply stick some masking tape to the center of the blade.
There are many ways to do this. Usually, it’s easiest to wedge a sturdy block of wood between the blade and deck of the mower to keep the blade steady while you loosen the nut or bolt. You can also use a vise or clamp if it’s more convenient. Some mowers have a reverse threaded nut holding the blade onto the spindle. Take note of the placement and orientation of any spacer washers or plates that come off with blade.
For ordinary cleaning needs, all you’ll usually need is a gloved hand or a dry rag. However, if it’s been a long time since you’ve cleaned your lawnmower, you may find it necessary to use a hose and a little soapy water to remove accumulated plant material and grime. If you do, dry the blade with a rag once you finish.
You may want to lay down a few pieces of old newspaper before you begin working to catch stray metal filings, making for easier cleanup.
The amount of dust you’ll produce from filing your lawnmower blades by hand is likely going to be fairly small compared to what you might generate from other projects. However, it’s still a smart idea to wear a standard face mask or respirator to protect your lungs from airborne dust and metal particles as you would for larger grinding projects. [4] X Research source
Ideally, when you’re finished, the blade should be roughly as sharp as a butter knife. [5] X Research source Lawnmower blades don’t have to be razor-sharp – they spin fast enough to cut the grass without this level of sharpness.
Make sure that the blade is oriented correctly when you mount it (this should be easy if you marked the downward-facing side earlier as directed). The sharp edge should be facing the direction of the spin and/or the direction of the grass catcher portal. Do not use a hammer to make the bolt tighter. A snug fit with a wrench or rachet is usually all you need. You should be able to feel the tightness of the bolt by simply turning the wrench.
To sharpen the blade, move it back and forth against the wheel of the grinder. As when filing by hand, you’ll want to maintain the original angle of the blade’s bevel as you sharpen it. You can also use a 4½ inch (11. 4 cm) hand grinder with a metal wheel.
To use your belt sander to sharpen the blade, invert it so that the belt is facing up and lock the trigger switch in the “on” position. [6] X Research source
Keep an eye on your grass after you use your mower to cut it. If the grass has a clean, smooth edge, your blades are sharp. If the grass is frayed or torn, your blades are probably too dull and should be sharpened.
One way to do this is with a special device called a balancer, which can usually be found at gardening centers or hardware stores. If you do not have a balancer, it’s still possible to balance the blade. Place the blade on a wooden dowel. If one side tilts higher than the other, file the opposite side of the blade, then test the balance again until the blade lies flat.
As an example of the amount of money you might expect to spend at a lawnmower repair shop, some locations charge as little as $10-15 per sharpening.
