Project Guide

How to Maintain Your Lawn Mowers

Change the Mower Oil
Steps to change mower oil.

Your mower is a big investment. To ensure it performs up to its maximum, make sure you change the oil at regular intervals. You’ll get better and increased performance, less costly maintenance and longer engine life. Be sure to use oil specially formulated for small engines to keep your engine running at its best.

  • Disconnect the spark plugs.
  • Use an oil extractor kit to remove oil from the compartment. Be sure to contain and recycle the old oil properly.
  • Add new small engine oil to the compartment up to the dipstick fill line.
Clean or Replace Your Air Filter
Steps to clean or replace your lawn mower's air filter.
  • Determine if you have paper or foam air filters.
  • Check your operator’s manual to determine if air filter pre-cleaner is required. If so, follow the instructions in the manual.
  • Replace paper filters when they look dirty (keep a few on hand). 
  • Plastic foam filters should be removed and washed with warm, soapy water. Air-dry thoroughly, then work about 2 tablespoons of clean mower oil evenly across the filter to lightly coat it.
  • Reinstall the filter according to instructions.
  • Reconnect the spark plugs.

Be sure to check the air filter a few times during the mowing season, particularly if the mower is getting heavy usage.

Fill Your Gas Can, Treat Your Fuel
Steps to keep your mower's gas ready to go.

Gas can go stale in as little as 30 days. Add a fuel stabilizer and treatment to keep gas fresh and protect your mower’s engine.

Blade Maintenance
 A broom brushing off the mower.
  • Brush off the mower after each use to keep debris from collecting on the blades.
  • A dull mower blade cuts unevenly and shreds the tips of grass blades, which then turn brown and give a lawn a beige cast that makes it look dry. The ragged ends are also entry points for disease. Sharpen the blades regularly to avoid these problems.
Change the Spark Plug Annually
Changing a spark plug.

Once a year when you change your mower’s oil, replace the spark plug.


  • Disconnect the spark plug wire and then remove the existing spark plug with a wrench or pliers. 
  • To ensure you purchase the right replacement plug, write down the code on your existing plug, consult your mower’s owner’s manual or just take the old plug with you when you go to purchase a new one. 
  • Screw in the new plug and reconnect the spark plug wire.
Semi-Annual Cleanings
Debris wrapped around the blade of the mower.

A couple of times a year, give the mower a good cleaning. 

  • With the gas tank empty, turn the mower on its side. 
  • Remove any debris that may be wrapped around the blade or caked up on the underside of the mower deck. 
  • Spray the underside of the mower deck hard with a garden hose to loosen dirt and dried-on grass. 
  • Scrub with a soft brush and soapy water. Then rinse.
  • Dry the mower thoroughly before storing.
Winterize Your Mower
Draining the oil from the mower for the winter.
  • After you’ve used the mower for the last time at the end of the growing season, empty the fuel tank by letting the engine run until it is out of gas. Leave the gas tank empty until spring. 
  • With the gas tank empty, remove the oil fill cap (if applicable) and turn the mower over to drain the engine oil into a suitable container for recycling. 
  • If your mower has an oil drain plug, use that instead of turning the mower on its side. 
  • Refill the engine oil reservoir per your mower manufacturer’s recommendations and then replace the oil fill cap.
Small Engine Oil Recommendations
Chart of engine oil types.

Different oil types are best at certain temperatures. Learn which one to choose for your climate.

  • SAE 30 - Warmer temperatures, most common oil for small engines.
  • SAE 10W-30 - Varying temperature range; this grade of oil improves cold weather starting, but may increase oil consumption.
  • Synthetic SAE 5W-30 - Best protection at all temperatures as well as improved starting with less oil consumption.
  • SAE 5W-30 - Very cold temperatures.
  • Vanguard 15W-50 - Varying temperature range. For continuous use, such as commercial lawn cutting or pressure washing.

When choosing lawn mower oil, use a high-quality detergent oil classified as “For Service SF, SG, SH, SJ” or higher. Do not use special additives. Synthetic oils are an acceptable oil at all temperatures. Use of synthetic oil does not alter required oil change intervals.


Walk-behind mowers:

  • Oil capacity is typically 15oz or 18oz*.
  • Change engine oil every 50 hours or annually, whichever comes first.

Riding mowers:

  • Oil capacity is typically 48oz or 64oz*.
  • Change engine oil every 100 hours or annually, whichever comes first.

Sharp blades and a well-cared-for engine will mean your mower keeps humming for years to come. Keep your lawn mower in tip-top shape throughout the year and you’ll maintain your lawn more smoothly.

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