Lawn Mower Maintenance 101

The heat is rising, the sun is shining, and the grass is growing...and growing, and growing. Summertime mowing can feel like a full-time job, and if your lawn mower isn’t in top condition, that job can feel like a real drag. Most folks don’t know the ins and outs of mower maintenance, which is why so many lawn mower graveyards exist. (It's also what keeps the mower salesmen in business!) Keep your mower alive and purring for years to come by learning how to properly maintain it.

A great lawn mower is an investment that you depend on, and its motor needs care. Change the oil at regular intervals to ensure the engine is well-lubricated. Make sure you use an oil specifically formulated for small engines. When changing the oil, first disconnect the spark plugs. Put old oil into a container and recycle it at an auto parts store. Finally, fill the oil compartment to the dipstick fill line with fresh oil, being careful not to overfill it.

Check your air filter a few times during mowing season. A clogged filter can make your engine run poorly, hurting the motor over time. Lawnmowers use two types of air filters: paper and foam. Check to see what type you have, and follow any special instructions in the manual. Replace paper filters when they look dirty. For a foam filter, remove and wash it in warm, soapy water and then allow it to air-dry completely. Once dry, spread a thin, even coating of clean motor oil across the surface and reinstall it according to the instruction manual. Reconnect the spark plugs.

Sharp blades are a critical component of mowing a lawn properly. After each mowing, brush off the mower blades to prevent the accumulation of debris. You also want to avoid mowing when the grass is wet. Your mower blades will dull faster. Dull blades cut unevenly and tear the grass instead of cutting it. This leaves your lawn susceptible to yellowing and disease.

Sharpening mower blades takes a little practice, but it's actually quite simple. For safety, you should wear cut-resistant gloves and disconnect the spark plugs. Remove the blade by turning your mower on its side, blocking the blade with a 2x4 and then loosen the single bolt holding it on. Mark your attached blade so that you know which way to put it back on! Secure the blade in a vise or clamp, and use a 10" file to hone the cutting edge.

File in one direction, and keep the angle consistent. Butter-knife-sharp is preferable to razor blade sharp, so no need to go overboard. A blade that's too sharp will dull much faster. Once you’ve finished both sides, hang the blade from a nail in the wall to check its balance. If it's heavier on one side, file a little more until it balances. An unbalanced blade can cause heavy vibration and ruin the blade shaft or bearings.

It's important to sharpen the blades at the beginning of mowing season, and again after every ten hours of use. You should replace them every two to three years. Many professional landscapers keep an extra set of blades on hand in case one gets broken or dull in the middle of a mow.