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When it comes to lawn mower maintenance, we usually think about ensuring clean fuel or dusting off the air filter.

But to improve your machine’s performance and keep it in top shape, you’ll need to clean the lawn mower thoroughly – from the handles to the mower deck.

When all parts are clean and in good condition, your mower will last longer and cut better. You could also save yourself from a hefty repair bill and a headache.

Here’s a breakdown of how to clean a lawn mower, part by part – so ready some elbow grease!

Before Cleaning | Cleaning After Use | Mower Blades | Mower Deck | Collection Box | Air Filter | Carburetor | Spark Plug | Gas Tank | Engine | Exterior


Why Clean Your Lawn Mower?

Like many other power tools, even the best lawn mowers need regular maintenance! Dirt, debris, and moisture can affect your mower’s performance and cause damage (such as rust).

A dirty mower deck can also reduce airflow to your engine and cause your lawn mower to overheat.

Moreover, a build-up of plant debris can lead to mould and other fungal growth, which can spread from your mower to your lawn.

Cleaning and maintaining your mower also helps you spot any issues sooner. By checking the different parts as you clean, you could spot broken blades or faulty spark plugs – and save yourself a bigger repair bill down the line.


When to Clean a Lawn Mower

Woman cutting grass with lawn mower in garden on sunny day

Give your mower a quick clean and once-over after every use. This helps prevent build-up and makes maintenance easier.

Every 25 hours of use, deep clean your lawn mower. You may need to do this more frequently if you do more intense work or if the weather makes it particularly dirty.

Perform thorough cleaning at the end of mowing season before you store the mower away. This minimises the risk of rust, mould, and hardened debris, and is especially important before winter.

At the very least, you should deep clean the mower twice a year.


Before Cleaning Your Lawn Mower

Always shut off your mower and let it cool before cleaning! Wear protective equipment as well (such as work gloves) to minimise your risk of injury.

Do not use metal cleaning tools (such as metal brushes) since these could scratch or damage the mower.


Cleaning a petrol lawn mower

petrol lawn mower

After shutting down the mower, look for the spark plug and disconnect the wires. This will help prevent any accidental starts and injuries.

You can also turn off the fuel valve.

Never tip a petrol mower on its side when cleaning, as this can cause the oil or fuel to leak out onto other parts of the engine. This is a common cause of white smoke from your lawn mower.


Cleaning an electric lawn mower

Always unplug your electric lawn mower before cleaning to avoid accidental starts and injury. If you use a battery-powered mower, remove the battery if the model allows it.

Minimise the use of water and moisture in general, as this could damage the electrical components and cause a short circuit. This could also become a fire hazard.


How to Clean a Lawn Mower After Use

Close up view of man hand brushing off layer of wet grass stuck to the bottom of the lawn mower.

After you’ve mowed the lawn and disposed of the grass clippings, give your lawn mower a once-over before storage!

This helps prevent dirt and grass build-up, keeps the blades in good condition, and decreases the risk of mould and damage.

Once the lawn mower is switched off and cool, start with the grass bag or collection box. Use a stiff-bristled brush (such as nylon) to clean out any dirt and stuck-on grass clippings.

Next, use the same brush to remove any loose dirt and grass from the outside of the mower, especially the base. Then wipe the exterior with a damp cloth to clean off mud and other caked-on dirt.

Follow your mower’s instruction manual about how to access the underside. Use a scraper or brush to remove any residue, such as wet grass or clumps of dirt.

Check the deck to see if you need to sharpen the blades. Otherwise, you can (carefully!) brush them clean or use a specialised cleaning product.

TIP: You can use a leaf blower or compressed air as well! A leaf blower is great for working on large areas, while compressed air can help with nooks and crannies.


Cleaning Your Lawn Mower: Part by Part

man changing lawn mower blades

At least once during the mowing season, you’ll need to give your lawn mower a more thorough cleaning.

Regular maintenance will make it easier to keep your lawn mower clean, but deep cleaning helps extend its lifespan and ensures everything is in working order.

Note that these steps apply to push or self-propelled mowers! Ride-on mowers have more components that may be hard to reach, and will need professional attention.

Always consult your owner’s manual for instructions on how to remove and reattach all parts.


How to clean lawn mower blades

Tip a petrol mower backwards (handles to the ground) or turn an electric model on its side (air filter facing up) so you can access the mower’s underside.

Set the blades to their lowest setting or remove them from their housing. Use a scraper or brush to remove any caked-on mud, grass, and other debris. Look for something like this Walensee Lawn Mower Deck Scraper and Brush.

Once they’re clean, inspect the blades for any damage – dullness, cracks, chips, or warping. A dull blade can be sharpened, but cracks or holes mean you need to change the mower blades.

Use your mower’s blade balancer (or get one like the Oregon Precision Blade Balancer) to make sure the blades are level.


How to clean the lawn mower deck

Use a wire brush or scraper to clean the mower’s cutting deck. Remove the caked-on dirt and debris, and check for any clogs.

(TIP: A putty knife also works in a pinch!)

You can use a leaf blower to dislodge any debris, especially in hard-to-reach spaces. Some people opt to use a pressure washer to “blast” off dirt, but be mindful of getting water inside the mower.

If you plan to use a blower or pressure washer, make sure you’re wearing protective gear (especially eyewear).

Check for any signs of rust or damage in the deck as well.


How to clean the grass box

man removing grass out of lawn mower box in the garden

Remove the grass collection box or bag and give it a good washing. You can use a regular garden hose and some dish soap, then wipe it dry with a clean cloth.

Regular cleaning helps prevent dirt, grass clippings, and other residue from building up inside the box, which could lead to mould and other fungal disease.


How to clean the lawn mower air filter

The air filter element prevents dust and debris from getting to the engine, and allows air to flow through to mix with the fuel and cool the mechanisms.

There are three types of air filters: paper, foam, and hybrid. It’s best to clean the air filter every few uses, except for disposable paper filters, which can just be replaced.

Paper filters can be gently brushed or wiped to remove dust. Foam and hybrid filters should be washed with soap and water, then dried thoroughly before putting them back.

Replace the air filter at least once per mowing season (about 300 hours of operation).


How to clean the lawn mower carburetor

lawn mower carburetor

The carburetor is part of the ignition system and supplies a mix of air and fuel to the engine. For push and self-propelled mowers, you’ll typically find it under the air filter.

Always check and clean the carburetor on its first use after extended storage (such as over winter). After that, you can maintain it every few uses, alongside the air filter.

You can clean the carburetor without removing it using compressed air and a dedicated cleaner, such as STA-BIL Carb/Choke Cleaner or Gumout Carb and Choke Cleaner.

Inspect the interior for exposed wires, corrosion, mould, or moss. Do not introduce any moisture as this can damage the engine.


How to clean the lawn mower spark plug

It’s not always necessary to clean a lawn mower spark plug, since they’re easy and affordable to replace.

But it’s still useful to know since you can prolong the lifespan of your current spark plug (especially if you can’t readily buy a new one).

Cleaning a spark plug is straightforward – simply remove it from its housing, then inspect it for damage. If it’s intact, dip a Q-tip into rubbing alcohol or WD-40 and rub the heads clean.

You can then use a soft brush to clean the threads and housing. Wipe off any dirt and excess cleaning product afterwards.

Change the spark plug every 25-30 operating hours, or at any signs of wear and tear.


How to clean the lawn mower gas tank

man cleaning fuel tank of a lawn mower

You don’t need to wash the gas tank (definitely do not introduce any moisture) but it’s worth checking on the fuel and oil.

Dark, murky, or dirty engine oil needs to be drained and replaced. Look for the drain plug or valve port, and loosen or remove it to drain the oil. You can also use an extractor pump.

After that, check the fuel tank. Gas that is dark, murky, or sour-smelling has gone bad and has possibly oxidised. Look out for any “gummy” debris floating at the top as well.

Drain the tank completely and fill it back up with fresh fuel (stabiliser optional).

However, if you suspect the bad fuel has been in your mower for an extended time (such as over winter), it may have gummed up inside fuel lines and other components.

That may require a more thorough cleaning of all the machine components, or even professional attention.


How to clean the lawn mower engine

Again, do not introduce any moisture to the engine or any components! At most, you can use an appropriate light solvent to dissolve stubborn dirt.

Carefully remove the screen and housing, then inspect the components for any damage or built-up debris. Use a small, stiff-bristled brush to clean the different parts, from screens to cooling fins.

For stubborn dirt, use a putty knife or scraper and scrape gently. Be careful not to damage the housing or flywheel.

Alternatively, apply a small amount of solvent with a brush to dissolve any dirt.

Check all cables and connections to make sure they are intact and not blocked. Make sure all the components are moving freely; apply appropriate lubrication if needed.

Reattach the housing and screen.

NOTE: Avoid using compressed air on the engine and any internal components, as this could blow dirt or debris further into crevices and make it more difficult to clean out.


How to clean the lawn mower exterior

man cleaning lawn mower exterior

Finally, clean the outside of your lawn mower! You can use a damp cloth or minimal water on the exterior to wash off any dirt such as mud or grease.

A stiff-bristled nylon brush can remove any grime from the exterior surfaces. Use a damp cloth to “rinse,” then dry the surfaces.

Wipe the handles and shaft with a clean rag and check for any warping, cracks, or nicks.

Apply any lubricant (such as WD-40) to any moving parts that feel stuck, such as the wheels or the height adjuster. Wipe off any excess product afterwards.


Common Questions about Lawn Mower Cleaning

Have more questions about how to clean a lawn mower?

Here are some handy details to know about mower maintenance.


Can I wash a lawn mower with a garden hose?

cleaning the lawn mower grass box with water hose

Yes – but only specific parts. Generally, lawn mowers can’t get wet as moisture in the system can cause damage to components like the engine.

Some lawn mowers have a “wash port,” or a port where you can connect a garden hose. The port allows you to pump water through the blades, which flushes out dirt and debris.

If you plan to use this feature, ensure the mower is on a flat surface and lower the deck as much as possible. You’ll also need to dry the mower thoroughly, or the blades could rust.

Surface-level water on the outside is fine, but the internal components should remain dry. Exposure to wet conditions or moisture can lead to rust, fuel or oil contamination, or short circuits in electrical models.


How to clean the underside of a lawn mower?

Follow the manufacturer’s instructions to expose the underside.

Then you can use a scraper, brush, or leaf blower to clear out debris and clogged dirt.


Which way do you tip a lawn mower to clean underneath?

Petrol mowers must be tipped backwards – meaning handlebars towards the ground. This will prevent oil from leaking out onto any internal components, especially the filter.

If you must tip a petrol mower on its side, make sure the air filter side is facing upwards.

Always detach the spark plug wire before tipping over the mower.

Electric and battery-powered mowers can be tipped backwards or sideways, so long as the air filter isn’t covered.

About Author

Jamie Donovan

Jamie is an Australian horticulturalist and landscape designer. He enjoys writing about landscape architecture, garden design and lifestyle topics.


About Author

Jamie Donovan

Jamie is an Australian horticulturalist and landscape designer. He enjoys writing about landscape architecture, garden design and lifestyle topics.