Cleaning riding lawn mower. How to Clean the Underside Deck of Your Lawn Mower

How to Clean the Underside Deck of Your Lawn Mower

David Beaulieu is a landscaping expert and plant photographer, with 20 years of experience.

It’s no surprise that there are many opinions on how often a lawn mower should be cleaned. This is largely a matter of personal preference—just as some people sweep and wash a kitchen floor daily, others may only do it weekly or even just monthly. The same holds true for outdoor lawn and garden tools. Some people with a robust neatness gene may prefer to clean lawn mowers and other garden tools thoroughly after every use, while others find no need to be quite so meticulous.

Even for people who routinely wipe down and brush off the top surfaces of a lawn mower, not everybody will turn the machine upside down and carefully clean off grass clippings and grime from the underside of the mower—the area known as the deck. Among those given to debating the issue, the question has three parts:

• Is it necessary to clean the mower deck? If so, why?
• If it is necessary, how often should I clean the mower deck?
• And how exactly should I do it?

A related but different question has to do with what TLC you should give the lawn mower when you are ready to put it away for another year.

Yes, the Lawn Mower Deck Should Be Cleaned

The reason for cleaning the deck—the enclosed housing beneath the mower, where the blade spins— has nothing to do with being neat (unless you are the type who takes pride in showing guests your power equipment). Cleaning will actually help lawn mower performance by allowing the blades of grass to stand fully upright as the blade spins to trim them. A lawn mower deck heavily encrusted with dried grass clippings may deflect the grass blades so they can’t be cut efficiently, and in worse-case scenarios, the dried grass buildup can even hinder the rotation of the blade itself.

Keeping the bottom deck clean also helps minimize the spread of lawn diseases. Remember, when you cut blades of grass, you are essentially opening up wounds that make the grass susceptible to problems such as fungal disease, which may be lurking in the grass buildup on the bottom of the mower.

Do It at Least Twice Each Mowing Season

There is no rule about how often to clean your mower deck, but it really should be done at least twice each mowing season. You may need to do it more often if you’re forced to mow very long grass or if you have to mow it while it is wet.

It’s also wise to clean the deck of your mower at the end of the season, before putting the mower away for the winter. It’s unpleasant to leave grasses to rot and mold on the bottom of the mower over winter, especially if you are storing your mower in an attached garage or basement. Left to harden over winter, your spring cleaning chores will be all the harder.

How to Clean the Deck on a Lawn Mower

To clean the deck of a lawn mower, follow these steps:

• Empty the gas tank (or run the mower until the tank is empty), then disconnect the spark plug wire.
• Stand the mower up on its side.
• Take a garden hose and spray the deck at full blast. This will loosen some of the dirt and caked-on grass clippings.
• Scrub off the rest of the soil, using a brush, soap, and hot water.
• Rinse, then dry the metal deck of your mower.

Tip: To reduce future incidences of grass clippings sticking to the lawn mower’s underside, lightly spray some vegetable oil onto the deck after cleaning it.

End-of-Season Maintenance

When the mowing season is over in the fall, empty the gas tank by allowing the lawnmower to run until its gas tank is empty. Leave the lawn mower‘s tank empty until spring comes, if possible. When old gas lies around in the lawn mower all winter, it becomes gummy and may foul the engine. If you must leave the tank full of gas, add a can of fuel stabilizer to the mower tank, then run the engine for a few minutes to distribute the stabilizer through the fuel lines and engine cylinder before putting the mower away.

After dealing with the gas, drain the oil crankcase and refill it with fresh oil.

These steps should make your lawn mower ready to go when you pull it out of the garage or shed next spring. But if you do end up having trouble starting your lawn mower, it may be because you need to tune up your machine, which is a fairly easy DIY task.

How to Clean Your Riding Mower Carburetor: Step-By-Step

Your riding lawn mower carburetor controls the amount of air and fuel mixture to form combustion in your engine.

When the carburetor isn’t functioning correctly, it can cause your riding mower to sputter, stall and not start. Most of the time, your carburetor problems can be solved by cleaning them.

If you are a little mechanical and don’t mind working with small parts, you can follow my instructions below to clean the carburetor yourself. Your local small engine repair shop is an option to have your carburetor cleaned or rebuilt if you don’t want to tackle the job.

Symptoms of a Bad Carburetor on Your Riding Lawn Mower

When a riding carburetor is acting up, you will notice these symptoms due to your mower running with the incorrect fuel-to-air mixture or having a blockage:

• Engine won’t start
• Starts and then dies
• Backfires from running lean
• Engine is sputtering and running rough
• Engine is surging
• Mower is consuming too much fuel

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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.

Steps to Clean Your Riding Mower Carburetor

Spray Carburetor Cleaner in the Air Intake: You don’t want to take your carburetor apart if it isn’t causing your problem. To identify if you need to take your carburetor apart, remove your air filter from the filter housing.

Spray carburetor cleaner into the air intake and start your riding mower. If your mower starts and then dies, you must take apart your carburetor and clean it.

Gather Tools and Items Required to Clean the Carburetor

• Pliers
• Screwdriver
• Socket/ratchet set
• Carburetor cleaner
• Thick wire
• Needle nose pliers

Take Photos for Reassembly

I highly recommend taking photos during the disassembly of your carburetor. There are so many small parts to your carburetor that it can be hard to remember where every part to when you reassemble it.

Most people have a cell phone available to take photos and easily access them. If you have a camera or phone, take photos of your carburetor before you remove it and during each step of taking it apart.

Shut off Your Fuel Supply

Use your fuel shut-off valve to stop fuel flow. You will find this valve at the bottom of your fuel tank. If you don’t have a shut-off valve, crimp the line to stop fuel flow. Remove the fuel line from the carburetor.

Remove the Throttle Choke Cable

Remove your throttle and choke cables.

Detach the Filter Housing

Remove the hardware that attaches the carburetor to the air filter housing.

Remove the Springs on Your Carburetor

Next, you need to slowly remove the springs. Be careful to not stretch out the springs. You may have to twist the carburetor a bit to get the springs to come off.

Be careful not to tear the gasket located between the engine block and the carburetor. If you do tear it, you will need to replace it with a new gasket.

Remove the Bowl from Your Carburetor

The carburetor bowl stores a little gasoline inside your carburetor. The bowl is located on the bottom of your carburetor and is held on by a screw. Have a rag available to catch any remaining gas in the bowl.

Go ahead and remove the screw and the bowl while taking care not to damage the gasket that sits between the bowl and the carburetor.

This gasket looks like a rubber Band. You don’t want any substance such as carburetor cleaner to get on the gasket or you will need to replace it.

Check the Stem for Clogged Holes

There is a little piece that hangs down from the center of your riding mower’s carburetor. This is known as the stem. There are holes in the stem that can become clogged from running old fuel.

When this happens, the stem will not draw fuel up to the jet. Use a flashlight to better see the holes in the stem. Clean the holes with a thick wire to unplug the holes.

Check Your Carburetor for White Crusty Buildup

Check out the carburetor and its parts for a white crusty buildup which is the result of fuel additives including ethanol. Try to remove as much of this crusty material as possible using carburetor cleaner. It is almost impossible to remove all the crusty deposits.

Use the carburetor cleaner to clean any parts that are sticking or clogged.

Reassemble Your Carburetor

Once you have cleaned your carburetor and ensured the float and float needle are moving freely, it’s time to reassemble it. Reference the photos you took earlier when putting your carburetor together to make sure all the small parts get put back in the right places.

Reattach components to your riding mower carburetor including the springs, filter housing, throttle and choke cables (if the mower uses them), and the fuel line.

Fill Your Fuel Tank with Fresh Gas with a Fuel Additive

Start your fuel flow. Use fresh gasoline mixed with a fuel additive, like Sea Foam Motor Treatment, in your riding mower’s fuel tank. Give the fuel a chance to fill the bowl of your carburetor and start your engine.

Read more about why I choose to use Sea Foam to stabilize and clean my fuel system with my article on the advantages of Sea Foam here.

Replace or Rebuild Your Carburetor

Sometimes cleaning your carburetor doesn’t get the carburetor working again. You may have too much buildup or parts of your carburetor may become stuck or damaged. In this case, you will have to rebuild or replace your carburetor.

Check the price for a carburetor rebuild kit and the price for a new carburetor. Sometimes the aren’t that far apart and you may choose to replace your carburetor instead of rebuilding it.

When purchasing parts for your carburetor, have your engine’s make and model number available. Many lawn tractors use another manufacturer’s engine so you need to have the engine information on hand to ensure you get the right parts.

Riding Mower Problems Could Be than a Carburetor Problem

A dirty or bad carburetor can be a cause of your riding mower not starting, quitting after starting, and leaking fuel. There are many other items that can cause these problems. To find out more about these causes and how to solve them, check out the links below.

Still Having Problems With Your Riding Mower?

As a lawn mower owner, when you own it long enough, you are going to run into different types of problems. This may include problems where your mower is smoking, cutting unevenly, losing power, not starting, leaking fuel, and more.

Check out this handy guide including charts for common mower problems and solutions:Common Riding Lawn Mower Problems Solutions.

If you are unable to fix your mower or don’t want to attempt a more complicated repair, have your local lawn mower dealership or repair shop for assistance.

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How To Wash Your Mower Deck (and Why)

Perhaps you’re not the type to keep your equipment spotlessly clean. However, washing your mower deck is important to protect the condition of your equipment and maintain your lawn’s health.

Why Should I Clean My Mower Deck?

You’re probably more likely to make the effort of cleaning your mower deck if you know why you’re doing it, so let’s review how this practice affects your mower and your lawn. First, you know those annoying grass clippings that tend to stick to the wheels and deck? Well, they look unsightly on your equipment, but they’re a problem beyond that. If enough grass clippings accumulate, the buildup can prevent your grass from standing upright, and you won’t get a clean cut. 1

If your mower blades can’t cleanly slice the grass, they’ll shred it instead, damaging your lawn.

When your lawn isn’t completely dry, it’s even worse. Damp grass easily forms clumps that will build up quickly underneath your deck. When that happens, your deck will retain moisture, creating the ideal environment for rust to form.

Additionally, the act of mowing essentially slices open your grass blades. This can make them vulnerable to things like fungus, and if the clippings underneath your deck are carrying that fungus, you can spread it out to the rest of your lawn. 1

This information should convince you of the importance of keeping your mower deck clean. But now another question arises. How often do you clean it?

How Frequently Should I Clean My Deck?

The answer to how often you should wash your deck can depend on your specific situation. Generally, you shouldn’t need to clean the deck more frequently than two to three times in one mowing season. However, if you have a larger yard or if your yard is in a wet or low spot, you’ll want to clean at least four times a season.

Plus, if you ever mow when your grass is wet or if you mow very long grass, you may want to wash your deck each time you use your mower.

Ultimately, use your best judgment and be flexible. Depending on how dry or how large your lawn is, you can increase or decrease the number of times you’ll need to wash your deck during the mowing season.

How Do I Wash My Lawnmower Deck?

Some mowers have a built-in washing feature that makes cleaning their decks easy. We recommend doing this immediately after you get done mowing so that the clippings won’t have time to harden. Put your mower on a clean, non-grassy surface, adjust the deck to its lowest height, connect the hose, turn on the water, and engage the blades.

If you’re working with a push mower without a built-in washing feature, begin here:

• Remove the gas in your tank or run the mower dry of fuel.
• Take out your mower’s spark plug.
• Put your mower on its side with the air filter and carburetor pointing up.

If you have a riding mower, do this instead:

• Engage the parking brake on your mower and put chucks behind the back tires.
• Lift the front end of your mower with a lawnmower jack.
• Once your mower is tilted high enough that you can clean it, secure the jack position to keep it there.

With those steps complete, it’s time to clean.

• Use a garden hose or a pressure washer to loosen grass clumps on your deck’s underside.
• If there’s debris that can’t be removed with water, use plastic tools, like a brush or ice scraper, to scrub it away.
• Give your deck a final rinse. Then be sure to dry it completely so that rust doesn’t form.

Check Your Mower Blades

Since your mower deck is accessible right now, it’s a great time to check your mower blades. You want to keep them sharp enough to slice your grass cleanly but not so sharp that they can cut your hand. (Ironically, over-sharpened blades dull quickly.)

If your blade is dull but appears to be in good shape otherwise, you should be able to sharpen it yourself, or you can have one of the pros at Outdoor Concepts do it. However, if you see any rust spots or large chips or dents, you’ll want to replace it.

Keeping your deck clean going forward

If you want to make future cleanings easier, you can spray a light coating of silicone lubricant—or even vegetable oil—inside your mower deck.

Additionally, at the end of mowing season, give your deck one last cleaning so that grass buildup, rust, and mold won’t be sitting on it throughout the winter.

Following these steps will increase your mower’s longevity while also benefiting your lawn. Got questions? Drop by our Bluffton or our Muncie location to chat with a member of our team.

This article was updated May 22, 2023

Lawn Mower Carburetor: When and How to Clean

Few pieces of home maintenance equipment work as hard as your lawnmower. Despite its rough-and-tumble life, though, many lawnmowers don’t get the care and attention they need.

This is especially true when it comes to the lawnmower’s carburetor. Your lawnmower’s carburetor is a critical component for functionality and will be the thing that determines whether your lawnmower works for years or conks out early.

With that in mind, learning to clean your lawn mower carburetor is a critical part of preventative maintenance. Here’s what you need to know.

When Should you Inspect and Clean a Lawnmower Carb?

While the exact recommendations for this vary from household to household, most experts say you should check and clean a lawnmower carb at least a few times a year.

The reason for this is simple: as you use your lawnmower, the grass, twigs, and debris the blade kicks up make their way into the small engine. Some of that debris eventually wind up inside of the carburetor – clogging fuel and air passages and reducing the performance of the mower’s engine.

Steps to Clean a Carburetor

Here are four steps to follow to clean your carb quickly and easily:

Start by Checking Your Air Filter

The first step in cleaning the carburetor is to check the air filter to ensure it’s free of debris. A clogged air filter will create black smoke that spills from the exhaust. It will also make it difficult for your carb to get the air it needs to “breathe.”

Check all Connections

Next, it’s time to check the connections that run from a carburetor’s throttle and choke plates, since these things can stick when they get dirty.

Additionally, constant vibration and wear can loosen screws over time, contributing to strange handling and additional carb issues.

Use Carburetor Cleaner

Next, it’s time to pick up a carburetor cleaner to get rid of the deposits within the carb, which can clog both air and fuel passages and interrupt the performance.

Fortunately, you can generally do this without even taking the carburetor out of the engine. Start by purchasing some commercial lawnmower carburetor cleaner, which comes in a simple spray can and will make it easy to clean the inside and outside of the carb.

After you’ve coated the surfaces of the carb with this cleaner, give the lawnmower a once-over for other maintenance issues, like stale fuel, bad air filters, old spark plugs, dirty engine oil, and more.

Check Settings

Now it’s time to check the settings on your carburetor to see if anything should be adjusted or updated.

If you’re not sure what you’re looking for, take your carburetor to a local repair service, which can help you identify issues and ensure you’re running your carb as efficiently as possible. This professional will also be able to help you understand why you shouldn’t drain the fuel and how best to care for your lawnmower in the future.

Keeping Your Carburetor Clean and Healthy

A critical piece of your engine’s functionality, the carburetor keeps your lawnmower running strong and functioning well. When you understand how to clean your lawnmower carburetor, you can keep your lawnmower in great shape for years to come, no matter how hard you use it.