How to Clean the Underside of a Lawn Mower

In Brief: How to Clean the Underside of a Lawn Mower

Clean the underside of your lawn mower manually or with water. To clean the mower manually, safely tip it on its side and use a solid tool to scrape away any caked-on dirt and grass. Brush or rinse the remaining dirt away. Alternatively, you can spray water through the washout port or under the mower and run the blade.

Grass clippings get everywhere. No matter how much grass you’re mowing, you can always count on clippings getting stuck on the underside of your mower.

If too much gunk collects there, your mower won’t work as it should and might cut poorly, stall, or run sluggishly.

Fix this problem by learning how to clean the underside of a lawn mower. It’s a simple process that only takes a few minutes for any make or model of mower.

2 Ways to Clean the Underside of a Lawn Mower

Depending on the design of your lawn mower, there are different ways to clean the underside. The best ways are to either scrape away the caked-on clippings by hand or to use water to wash the debris away.

Method 1: Scraping

The simplest way to clean any lawn mower deck is to scrape all the debris off. This is possible on any type of lawn mower, regardless of the specific design.

  1. Step 1: Prepare & Flip Your Mower

    To scrape the debris off the bottom of the mower, you’ll need to turn it on its side to access the mowing deck on the underside. Before you flip your mower on its side, close off the oil and gas tanks securely. Disconnect the spark plug.

    Remove the fuel tank and place a thin piece of plastic over the top. Screw the cap back on top the plastic. Do the same thing for the oil tank. Make sure you lean the mower to the side where the oil tank sits to avoid spilling oil into the carburetor or the engine itself.

    Once the mower is prepared, turn it to its side and rest it on the ground. You may remove the blade if you would like easy access to the mower deck, but it’s not necessary. If you are already planning to sharpen the blade, removing it before cleaning is convenient.

  2. Step 2: Scrape Away Grass

    Scape all visible chunks of grass clippings and dirt that are caked onto the underside of your mower. Use any metal tool available, such as a screwdriver, ice scraper, or something similar. You can also choose to do it by hand, but you should wear a glove to protect your hand from the blade edge.

    Make sure you remove all the grass you can, including the stuff on the edges of the mower deck and around the blade. It may be helpful to use a tool specifically designed for scraping a mower deck, to help you clean properly around the curved metal.

    As you scrape away debris, remove it from around the mower deck to get a clear idea of how much dirt is still left.
    See an example of a grass scraper here>

  3. Step 3: Cleaning Up

    Once you’ve scraped away the clumps from the mower deck, inspect it to see if there’s still noticeable debris on the metal. You can leave it as is or remove the small dust and grass bits left behind.

    Anything you have available can be used to clean off the remaining dirt. Take a hose, a sponge, a brush, a rag, or something else and remove the rest of the debris from under the mower. This is especially useful if there’s oil or another sticky substance on the mower deck.

    Once you finish cleaning everything, put the mower back on its wheels. If you used any water in your cleaning, put the mower in an open area to dry before storing it.

Method 2: Washout

Some lawn mowers have a built-in washout port on top of the mowing deck. This allows for simple washout cleaning. Even without a washout port, you can still use a hose to clean your mower deck to some degree.

Step 1:

Take your mower to a clean, clear area that’s nearby a hose and drainage. Check for a washout port on your mower. You’ll notice a small hole on the top or side of the mowing deck, large enough to fit a hose nozzle. Connect a hose into the washout port and proceed to step 2.

If there is no washout port, you won’t be able to connect the hose directly to the mower safely. Instead, place the mower over concrete, asphalt, or another hard surface free of any rocks or debris. You can hose it off beforehand.

With no connection port, you can lay the hose down on the ground about a foot away from the underside of the mower. The water should run directly underneath the mower when you turn it on.

Step 2:

Turn on the water, then turn on the mower. Keep the mower running until you see clear water coming from underneath. The water you see initially should be full of grass and dirt chunks.

When the water runs clear, turn off the mower then the water. Tip the mower over slightly to check the underside. If it’s clean, leave it. If it’s still dirty, you can take the hose and spray it again or scrape away the dirt with your hands or a tool.

Before you scrape the underside, disconnect the spark plug and put plastic under both the gas and oil tank caps. You can then tip the mower on its side safely without spilling anything. Clear off any remaining debris from the mower. Rinse again with water if you want to get rid of all the pieces you’ve scraped.

Note: Don’t use a pressure washer to wash a lawn mower. Pressure washers can force water into the engine or other sealed areas where to will cause real damage. It’s safest to use a regular water hose.

Step 3: Drying the Mower

To dry the mower, put it right side up and turn it on. Allow it to run for a few minutes without moving to get airflow under the mower deck.

If you had to tip the mower over, make sure you put it back on its wheels and remove the plastic from underneath the gas and oil caps before turning the mower on.

Once dry, the mower is ready for storage or use again. Watch this cleaning method in action:



Cleaning your mower is essential to keeping it in great shape. Whether you’re scraping the dirt away manually or washing the mower with water, do it regularly. Make cleaning a part of your normal mowing routine.

Do you have questions about cleaning the underside of your lawn mower? Below a comment below.

About Stephanie Hall

Stephanie is a DIYer and expert in using power tools. She is an architect and also provides design services. A yoga lover, she meditates to keep herself fit.

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