DIY Guide to Lawn Mower Maintenance

To keep your lawn in looking its best, your lawn mower must be well maintained.

Neglect your lawn mower, and it will inevitably develop problems, making it much less effective, and have shortening its working lifespan.

Properly maintaining your lawn mower will take less than an hour. It will be time well invested in ensuring better mower performance.

This lawn mower maintenance guide reviews everything to keep your mower running sweetly. And how to winterize your mower.

How to change lawn mower oil

Performing an oil change on a lawn mower

Changing the oil regularly will ensure your lawn mower is working optimally. An oil change is required when the mower oil turns black or includes debris. Draining and replacing the oil will improve the mower’s performance, help avoid expensive repair bills, and extend the engine’s lifetime.

Typically, a manual mower will need around 15-18 ounces of oil. You should change the oil after 50 hours of use or once per year, depending on whichever occurs sooner.

Ride-on mowers will need around 48-64 ounces of oil. You should replace the oil after 100 hours of use or each year, whichever occurs first.

Always remove the spark plug lead before changing the oil.

Get a suitable container to catch the old oil. If there’s no oil drain plug, you will need to purchase an oil extraction kit instead.

Replace with fresh oil and fill until you reach the oil level line.

Always dispose of old engine oil properly.

How to clean/replace lawn mower air filters

Someone changing the air filter on an orange lawn mower

A clean air filter is essential for the smooth running of the engine.

Check your mower’s manual to establish which air filter you have. Typically, it will be a paper filter or one made from foam. The manual will also tell you if you need to use a pre-cleaner.

Again, disconnect the lead fitted to the spark plug before removing the filter.

Paper air filters should be replaced whenever they look unclean.

Foam filters need to be removed and cleaned with warm water and detergent. Stand them to air-dry before working about two tablespoons of fresh oil into a light, even coat over the filter surface.

Replace as per the manual’s instructions and refit the spark plug lead.

Pro tip: Check the filter regularly, especially after heavy use.

How to treat the fuel

Gas will only stay fresh for around a month. It’s best not to use stale gas to protect the engine. To give fuel a longer shelf-life, add a fuel stabilizer to keep the gasoline fresher for longer.

Pro tip: Never use fuel that has been in over winter storage.

How to maintain mower blades

Sharpening a lawn mower blade on a grinder

The blades are the literal cutting edge of your mower. They, therefore, come under a tremendous amount of stress from everyday use as well as the occasional unseen rock or tree root.

Dull blades are simply incapable of cutting grass evenly. The ragged blades of grass invite disease and will turn brown.

Brush the blades after every use to prevent the collection of debris.

Regularly ensure the blade is still sharp. First, disconnect the spark plug lead before the blade.

You can then manually sharpen your blade using a grindstone or file while maintaining the blade at a 45-degree angle.

If you have a bench grinder, sharpen the blade with this, but always protective eyewear.

Check out our full guide to sharpening lawn mower blades for a more detailed overview!

How to replace spark plugs

A close up view of someone changing the spark plug of a lawn mower

You should replace your lawn mower’s spark plug at the start of each cutting season.

Disconnect the lead on the spark plug and carefully remove the old spark plug using pliers or a wrench.

Be sure you have the correct replacement spark plug. There’s a code stamped on the existing plug but double-check the recommendation in the owner’s manual. Or take the plug along when you are buying the replacement.

Carefully fit the replacement spark plug. Refit the lead onto the spark plug.

How to keep your lawn mower clean

Someone cleaning the underside of an orange mower, an important part of lawn mower maintenance.

It’s a good idea to give your mower a thorough cleaning twice a year or so.

Ensure you have an empty gas tank, then flip the mower sideways. Remove all the grass debris that has collected on the blade and the underside.

Loosen any stubborn deposits with a hose, then scrub with a brush dampened in soapy water. Rinse thoroughly with the hose.

Allow the mower to dry out before being stored.

How to prepare your mower for winter

When you are on the last cut of the mowing season, run your mower until it runs out of fuel.

When you’re sure the fuel tank is empty, the next fluid to drain is the oil. You can do this using the oil drain plug if fitted to your mower or via the oil fill cap by flipping the mower onto its side. Have a suitable container to collect the oil for recycling.

Replace the oil with fresh lubricant as per the manufacturer’s recommendations and replace the filler cap.

Store your mower in a weather-proof garden hut or workshop. However, do not place it beside a furnace or water heater.

Pro tip: To help engine starting at the beginning of the new season, some lawn mowers benefit from a squirt of water repellent spray into the spark plug chamber and the carburetor.

How to choose the correct grade of oil

Choosing the correct type of oil plays an essential role in getting the best out of your mower. The type of oil you require depends on your climatic temperatures.

SAE 30:  This oil is best suited for warmer climates and is the most widely used in lawn mowers.

10W-30: Opt for this grade if you have varying summer temperatures. This grade is best for cold-weather starts but may lead to increased oil usage.

Synthetic 5W-30:  This synthetic oil grade is an all-rounder, offering superior performance at a range of temperatures, improved starting, and reduces the consumption of oil.

5W-30: Specifically formulated for colder climates.

5W-50:  A great choice for a wide temperature range, heavy use, or commercial grass cutting.

Pro tip: Always buy high-quality oil that’s labeled for SF to SJ service, or better. Avoid using special additives, but bear in mind synthetic oils operate well across a wide range of temperatures. However, using synthetic oils will not change how frequently the oil needs to be replaced.

Additional lawn mower maintenance tips

  • Vibrations over time will cause nuts, bolts, screws, and wheels, etc., to loosen. Now and again, check all the fasteners. Tighten up any as required.
  • With electric mowers, occasionally check the battery and cord for wear and tear. Always store these peripherals in a dry place.
  • If you own a ride-on mower, always change the fuel-line filter annually and keep the tires at the correct pressure. Replace any damaged wheels.
  • Before mowing, always remove hazards that could harm your mower.
  • Only mow dry grass as this will prevent clogging of the grass clippings.
  • Never use a blade that’s cracked or dented. Replace it with a new blade to spare your lawn from damage.
  • Most mower maintenance is simple. However, if you are time-poor, be sure to get a professional to tune up your mower.


Sharp blades and an engine that’s well maintained will ensure years of trouble-free mowing.

Being consistent with maintenance will not only ensure your mower will last, but it will also ensure your lawn looks its very best.

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