How Do I Tune Up My Lawn Mower?

By mid-summer, you've likely worked yourself into a steady mowing routine - you know what day of week, what time of day and how often you need to mow, and may even rotate when you bag clippings or not. However, with regular mowing comes added wear and tear on your mower, which can lead to larger maintenance problems and hinder the overall performance of your mower, leaving you with a lackluster cut. 
 
With some light, quick maintenance, though, you can prevent such issues from surfacing. Consider these five mid-summer tune-up tips to help your lawn mower run at peak efficiency, plus keep your lawn looking fresh mow after mow.

 

Change the Oil

As with any repair or tune-up, always remove the spark plug wire and review your owner's manual before performing maintenance, and wear the necessary safety equipment. Oil changes are recommended about every three months, depending on frequency of use. Unlike an automobile, changing the oil in your lawn mower only takes about 15 minutes and costs about $2, which is money well spent in the end. Changing your mower's oil is one of the single most-important steps to maintaining its longevity, as it will keep your engine running smoothly.
 
For best results, run the engine for a few minutes before changing the oil. This will warm the oil and allow it to drain more easily. Once the mower has run for a few minutes, stop the engine, let it cool and empty the old oil into a suitable oil drain pan. For a walk-behind mower, you can drain oil from the dipstick tube using an oil siphon or by tilting the mower so the air filter and carburetor are facing upwards to drain excess oil. For a riding mower, drain remaining oil by removing the oil plug or siphon from the dipstick tube. Change the engine oil filter if your model is equipped with one.  Once oil is drained,  replace the drain plug and fill the mower with oil until it's visible through the oil fill hole, or check the level on the dipstick, if so equipped.

 

Replace the Air Filter

A clean air filter helps maintain a proper fuel-to-air ratio, allowing your mower to burn less gas. With consistent pollen, dirt and debris, your air filter can easily get clogged up throughout the summer.
 
To replace the air filter, start by loosening the air filter cover screw and removing the cover. Once the cover is removed, simply pull out the old air filter and press in the new one, with the filter pleats facing outward. Finally, replace the cover and firmly tighten the cover screw.

 

Sharpen the Blade

A sharp mower blade provides a clean, even cut and will prevent your mower from ripping grass from the roots, which can make entire areas of your lawn more susceptible to disease and damage.
 
Before sharpening the blades, make sure to wear a pair of thick gloves to avoid injury. To sharpen your mower blade, you'll first have to remove it. Before removing the blade, make sure to drain your gas tank so you don't leak any fuel. Once you've done so, you can begin by positioning your walk-behind or riding mower. For a walk-behind, tip the mower on its side to remove blades. For a riding mower,  it's best to use a mower jack so you can easily elevate the mower, and safely tend to and remove the mower blades. Another option is to remove the cutting deck following the instructions in the manual. Once your mower is positioned, you can begin removing the blades.  Use a blade removal tool or wood block to prevent the blade from turning and loosen the blade hardware using a wrench or breaker bar and socket. While you're removing the blade, be sure to take note of the blade's orientation so you can properly reattach it.
 
To sharpen the blade, simply secure it in place and run a metal file along each side of your blade's edge ensuring to maintain the balance from side to side. As an added precaution, make sure to wear a face mask or respirator to avoid inhaling any metal dust from the filing.

 

Replace the Spark Plug

Spark plugs are often replaced on an annual basis, so if you replaced yours in spring, don't sweat it this time - if you skipped out at the start of the season, you could probably use a fresh one. New spark plugs will make a noticeable improvement in the way your engine starts and runs, particularly in older mowers.
 
To start, simply pull off the spark plug wire and remove the old plug using either a spark plug wrench or a deep socket wrench, usually 13/16 in size. When inserting the new plug, hand-turn it until the threads catch, then use your socket to fasten the plug down until it stops on its own - don't force it. Once the plug has stopped, turn it one more quarter turn. Tightening the plug too much can damage it or make it very difficult to remove when it comes time for replacement. 
 
If the plug is rusted tight, spray it with a penetrating lubricant and let it soak in for 10 minutes before trying to loosen the plug once more.