How to Change the Oil in a Lawn Mower, and Other Mower Maintenance

Lawn mowers, just like cars, benefit regular upkeep. The good news is the maintenance doesn't require a mechanic, or really any prior knowledge or experience working with engines.

In this article, we'll go over a few actions that keep your lawn mower in tip top shape.

1. Lawn Mower Oil Changes

Changing the oil is a quick job that can keep your mower running smoothly for many seasons.

This 10-minute task doesn’t require any special tools or prior knowledge or experience working with engines.

How often should I change the oil in my lawn mower?

Note: you’ll only need to change the oil on four-stroke engines. Two-stroke engines (and electric mowers) do not need oil changes.

What kind of oil does my lawn mower take?

The kind of oil you should use depends on your climate. Use this guide to determine what’s best for you:

SAE 30: In warmer climates, this is the most common oil for small engines. Use in temperatures below 40 degrees F will result in hard starting.
SAE 10W-30: This grade of oil improves cold-weather starting when temperatures drop below 40 degrees F, but also increases oil consumption (especially in warmer weather)
Synthetic SAE 5W-30: Like SAE 10W-30, this grade allows for easy starting in cooler temperatures but with less oil consumption.
SAE 5W-30: This is better for colder climates (under 40 degrees F) In case you were curious, these numbers indicate the viscosity (how thick the oil is) at a cool temperature and then at operating temperature.

How much oil does a lawn mower hold?

A walk-behind mower typically takes 15oz or 18oz, whereas a riding mower typically uses 48oz or 64oz. You should check your lawn mowers manual to be sure (you can also do some research on the internet for your engine model).

What you’ll need:

New oil
Oil pan (any shallow container will do)
A couple of sheets of paper towels

Before you start, I recommend starting the mower and while its running turning the fuel shutoff valve located on the fuel line. Keep the mower running until it dies (this can take a few minutes) and you’ll have an empty carburetor that won’t leak gasoline on you while you’re tipping the mower on its side to change the oil.

Change Lawn Mower Oil

Frequency 90 Days

On a new lawn mower, it’s recommended to change the oil after the first 5 hours of use. After the initial oil change, you should plan on an oil change every 20-50 hours of use or at least once a year. Note: you’ll only need to change the oil on four stroke engines. Two stroke engines (and electric mowers) do not need oil changes.">

Begin by removing the dipstick (usually grey and labeled “OIL”) from the side of your mower and set it on a paper towel or somewhere where it won’t get dirty -- you don’t want to introduce dirt into your oil system when you put it back in.
Next you can place the oil pan adjacent to the mower, or if you’re using a small container like pictured here, it’s best to hold the container right below the oil tube to minimize potential spillage.
Slowly tip the lawn mower on its side and you’ll see oil will begin flowing out. Set the mower completely on its side for a minute or two to make sure all the old oil is emptied.
After the oil reservoir is empty, tilt the lawn mower back up on to its wheels. Fill the mower with the appropriate amount of new oil (check you mower’s manual if you’re not sure what that amount is). A funnel or flexible container can reduce any chance of spillage.
Wipe the dipstick clean, and insert it back into the mower. Remove it once more and check the level. If it looks good, your all set! If it’s beyond the max line or under the fill line, adjust as necessary by adding more or removing some using the same method outlined above.

2. Sharpening Lawn Mower Blades

Sharpening the blade on your lawn mower is a quick task that is not only rewarding because, hey, who doesn't love a nice sharp blade, but also because you'll notice the difference right away. Tall, damp grass is no match for a sharp blade. Your mower will cut through thick thatches like butter!

What you’ll need:

Blade sharpener
Safety goggles

There are a couple popular blade sharpeners on the market. If you already own a rotary tool than Dremel makes a great accessory with an attachment for lawn mowers, hedge trimmers, and chainsaw blades. If you don't own a rorary tool, seriously consider picking one up. They make quick work of jobs like these.

As with oil changes, to avoid emptying your carburators contents of gasoline all over the mower and lawn, tart by running the mower with the fuel shutoff valve closed for a few minutes until the engine dies.

Lawn Mower Blade Sharpening

Frequency 30 Days

If you cut your own grass, chances are you've flinched at the sound of a nice big rock coming into contact with your blade spinning at 3000 RPMs. Rocks, sticks, and just general use puts a lot of wear and tear on your blades. The good news is that you can DIY sharpen your lawn mower's blades whenever you want in about 10 minutes.">

This action requires a rotary tool and blade sharpening attachment. If you don't already own a Dremel or something like it, seriously consider purchasing one. They're relatively cheap and can make quick work of tasks like these.

Sharpening Lawn Mower Blades Using a Rotary Tool

Attach the lawn mower blade sharpener to your rotary tool
Flip your mower on it's side (you can also remove the blade and secure it in a vice, but that's not necessary for a simple walk-behind mower)
Clean any excess dirt & debris from the blade
Set the rotary tool to 25 (x1000 RPM) and turn on
Use the plastic guide to keep the angle of the stone consistant against the beveled edge of the blade
Move the the tool back and forth to form a nice, smooth edge
Sharpen each side of the blade for about an equal amount of time as to keep the blade as balanced as possible (an unbalanced blade can be wobbly when the mower is on)