How to Tune Up a Lawn Mower

A basic lawn mower tune- up involves three steps: changing the oil, the air filter, and the spark plug.

Your mower owner’s manual will tell you how often to change the oil. It’s particularly important to follow the manufacturer’s specifications if you’ve got a very large lawn or if you’re a commercial mower. For everyone else, changing the oil once a year is usually enough (unless you have one of those fancy new mowers where the oil needs to be refilled instead of changed).

Some mowers, especially bigger riding mowers, have a drain plug. If yours doesn’t, just tip the mower on its side and let the oil drain out of the filler. Warming up the mower will help the oil flow more quickly, but you should do this with caution, as the oil and the mower itself can get hot.

Once the oil has drained, replace the drain plug (if applicable) and fill the engine with the recommended amount and grade of oil.

Note: Always dispose of motor oil in accordance with local regulations. Motor oil can contaminate soil and water, harming people, plants, and wildlife.

The air filter helps a lawn mower run better by maintaining the right air/fuel ratio. But since it sits down in the dirt, it can easily get clogged with pollen, clippings, dust, and other debris. Fortunately, it’s an easy part to change.

Most air filter boxes unclip or are held closed by a simple screw. Just pop it open to remove and replace the air filter.

Hard starting, shaking, and bogging down are all signs that your mower needs a new spark plug. The spark plug ignites the air and fuel mixture, and it breaks down over time.

To change the spark plug, start by removing the spark plug wire. Examine the plug wire casing, especially the boot. There’s no point replacing the plug if the wire is damaged.

Removing the spark plug wire is a good first step when doing any kind of mower maintenance. With the plug disconnected, you don’t need to worry about accidentally starting the mower.

Next, remove the spark plug using a spark plug socket. These sockets are designed to hold the plug as you remove it so that it doesn’t fall back into the spark plug hole. This is handy when the plugs are in a hard-to-reach location.

Finally, put in the new plug and re-attach the plug wire. Just like that, you’ve finished your basic mower tune-up.

If you’re not sure what parts to get, complete tune-up kits are available for many mowers. They come with oil, a filter and plug, and often fuel stabilizer, which keeps your mower running smoothly.

In addition to changing the oil, filter, and spark plug, ensuring the blade stays sharp is essential to maintaining your lawn mower’s performance.

The blade is a key part of push and ride-on lawn mowers. A dull blade doesn’t cut—it rips or tears. You can have your mower blade sharpened at a lawn mower repair shop or you can sharpen it yourself at home with a grinder and file. If the blade is badly damaged from hitting too many rocks, it may be easier and cheaper to replace the entire thing.

The specialists at your local NAPA Auto Parts store can help you find the right blade for your mower.