Where is the Carburetor on a Lawn Mower? (Every Mower)
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I’ve always enjoyed using my cordless walk-behind push mower – no pesky cord to haul around and no gas to fill in the tank. But when I need a surge of power to complete larger jobs with ease, my go-to choice undoubtedly is my robust 140cc Briggs Stratton gas push lawn mower.
The downside however of using a gas-powered lawn mower is maintaining the many different parts like the air filter, spark plugs, hoses, and several other parts under the hood including the lawn mower carburetor.
Of all these aforementioned parts, the lawnmower carburetor is often the most overlooked but is in fact one of the most important parts of a mower just like a lawn mower engine that requires a fair bit of maintenance including annual maintenance.
What is a LawnMower Carburetor?
All gasoline-powered lawnmower engines are fitted with a carburetor. Similar to your car or truck engine, a carburetor helps run the small engine of a push lawn mower, self-propelled lawnmower, or riding lawnmower.
What Does a Lawnmower Carburetor Do?
The only goal of a lawnmower carburetor is to ensure that the right mixture of fuel and air enters the engine cylinder to trigger combustion.
This component of a lawnmower adjusts the balance of air and fuel based on myriad different factors including the amount of time the engine has been running, your speed, and the type of terrain you’re mowing.
Unlike automobile systems, a carburetor of a lawnmower doesn’t contain any throttle butterflies (a pivoting flat valve controlled by the gas pedal) but contains a rubber-type push bulb, through which fuel is primed when the bulb is depressed several times on a push-type lawnmower.
The fuel from the fuel tank flows through the bulb via a hose into the carburetor, which typically allows gas to drip into the carburetor bowl.
The engine creates a suction on the carburetor which mixes the gasoline with air at a specific ratio. After the carburetor has been primed, you can use the pull rope to start the engine.
What Does a Lawnmower Carburetor Look Like?
Most lawnmower carburetors look similar, with a small metal component complete with levers and springs and a distinct bowl shape under the carburetor body.
The carburetor float bowl accommodates the fuel and provides a continuous supply of fuel to the carburetor mixture as required.
The float bowl of a lawnmower carburetor can be drained with either the onsite drain bolt or screw without dismantling the whole system.
Where is the Carburetor on a Lawnmower?
This depends on the type of lawnmower you’re using, whether push, self-propelled, or riding lawnmower.
Where is the Carburetor on a Push Lawnmower?
Just as the name suggests, a push mower is any type of mower that you walk behind and push. The carburetor of a push mower is tucked away neatly behind the air filter at the side of the machine.
If you can locate the air intake filter or air filter of a push lawn mower, you’re one step closer to finding its carburetor. Depending on the machine, the air filter of a push mower is typically encased within a metal or plastic shroud and secured by a screw or with snap fittings.
Where is the Carburetor on a Riding Lawnmower?
The carburetor of a riding lawnmower is located just beneath the hood under the engine blower assembly so you’ll have to undo the hood latches of the engine hood to access it.
Similar to walk-behind mowers, the carburetor of a riding lawnmower is located behind or below the air filter, so once you remove the filter, you can spot it easily.
Signs a Lawnmower Carburetor is Dirty or Damaged
Old Gasoline
Old gasoline is the biggest enemy of a lawnmower carburetor regardless of the type of engine whether Briggs Stratton or brands including John Deere.
Your lawnmower will still run on old gasoline but it won’t offer the same top-notch performance that you’re used to.
This is why it’s highly important to empty the lawnmower gas tank when storing the machine for the off-season because old gasoline creates what is known as shellac in the fuel system.
This shellac blocks the inner workings and the air and fuel jets in the carburetor, which further prevents the fuel and air from passing through it.
A clogged gas line can be detrimental to the entire fuel system including the fuel filter, and mower air filter, and may even emit black smoke, which indicates that the machine is “running rich,” or burning too much gasoline.
The only solution for a gummed-up carburetor is a thorough cleaning, which involves removing the carburetor – a task you can do at home rather than visiting a lawn mower engine repair shop.
How to Get Rid of Old Gas in Lawnmower?
Before getting rid of the old gasoline from the lawnmower, check to see if it’s contaminated by pouring some in a glass container, pouring some fresh gasoline in another container, and then comparing them alongside.
If the old gasoline is darker or has a sour smell than the fresh gas, it is probably losing or has lost its efficacy.
Ideally, it’s best to get rid of the old gasoline from the lawnmower completely, but you can try diluting it with fresh gasoline to see if the performance improves.
You can transfer the old gasoline from the machine with a funnel into a jerry can or plastic can jug.
Engine Won’t Start
There could be several reasons why your lawnmower engine won’t start, most notably a dirty air filter, loose, dirty, or disconnected spark plug, and/or fuel not reaching the engine, which may be caused by a faulty carburetor or fuel filter.
If you’ve cleaned the air filter and checked that the spark plug and spark plug cable are connected securely, and you’re still facing the issue, making a few adjustments to the carburetor may help.
There may be many issues with the carburetor such as it’s dirty, the diaphragm is cracked or distorted, and/or it’s simply not getting the proper mixture of air and gasoline.
Your lawnmower’s carburetor and engine are protected against debris, dirt, and grass clippings by air filter guards. It is always a good idea to ensure they are clean and in perfect working condition:
How to Perform Lawn Mower Maintenance?
Maintaining your lawn mower will improve both its performance and service life. Lawnmower maintenance can be carried out at any time of year but the two best times are before the first mow of the season and at the end of the season when it’s time to retire the mower.
Many people choose to take their mower to a professional repair shop for maintenance but these simple checks and fixes can be performed in the comfort of your home.
Since every lawnmower model is different than the other, it’s best to refer to your owner’s manual for maintenance instructions but here are some common tips to keep your mower in tip-top shape.
Replace the spark plug
Removing the spark plug ensures that the mower doesn’t accidentally start. A lawnmower spark plug should be changed every mowing season, after 25 hours of use, or if the mower won’t start.
What You’ll Need On Hand to Clean Your Mower’s Carburetor
Before you head out to your lawn mower, you need to gather some tools and a few bits and pieces. Here’s a list of all the materials you’ll need.
How to Clean a Lawn Mower Carburetor (A Simple Guide)
There are a whole bunch of carburetors available for lawn mowers and each requires a slightly different method of cleaning. But generally, the steps stay the same. So, let’s have a look at what you’ll need to do.
Lawn Mower Cleaning
The first step is to clean off the outside of the carburetor. I find that WD-40 and a small nylon brush, like a toothbrush, work best. Anything more aggressive than nylon could damage the soft alloy metal of the carburetor.
You want to make sure to get all the clippings and dirt off the outside of the carb so that nothing falls into the engine when you remove the carburetor.
Removing the Carburetor
Start by removing the cover of the air cleaner and pulling out the air filter. You might need to use a screwdriver to remove the cover. Once you get both items removed, set them aside for later.
The next step is to remove the air cleaner base. This is the back of the air cleaner that the filter sits inside. So take your socket wrench and remove the bolts that hold the base to the carburetor. Again, set these parts to one side for later.
Now, it’s time for the fuel line. If your lawn mower has a cut-off valve, then switch it off. This will stop fuel from leaking from the fuel tank. If your lawn mower doesn’t have a valve, then a pair of fuel line pinch-off pliers will work fine.
Next, take a pair of pliers and remove the fuel line clamp. You’ll just need to move the clamp an inch or two down the fuel line. Once you have the clamp moved, slide off the fuel line. I find that giving it a twist at the same time as pulling helps to get the line off.
Now it’s time to disconnect the carburetor from the engine. So, take your socket wrench and remove the bolts holding the carburetor to the engine. Once you remove these bolts, the carburetor should come free of the engine, so be careful it doesn’t fall.
The throttle link cable is the final thing holding the carb to the mower. You can easily remove this link by using your pliers. Once you get the link off, you should be able to pull the carb completely away from the mower.
Dismantling the Carburetor
So, tip the carburetor upside down and locate the fuel cup’s center bolt. Use your socket wrench to remove the bolt, then remove the fuel cup from the carburetor.
Then take your needle nose pliers and remove the pin holding the float in place. Once the pin is removed, the float should come away from the carburetor.
Now it’s time for the jet. If you look where the cup bolt screws into the carburetor, you’ll find a screw. Use one of your screwdrivers and remove the bolt, being careful that the jet doesn’t fall out as this screw is holding it in place. Next, tip the carb into your hand so that you can catch the jet. It should fall out, but it might need a bit of help.
Cleaning the Carburetor
Now that you have the carburetor stripped down, it’s time to run through how to clean a lawn mower carburetor. So, grab your carburetor spray cleaner and give the whole carb a good spray. Allow the spray to soak into all the dirt and grime. Carb cleaners also act as a degreaser, so they will take care of the grease and oils on the outside.
Next, use your brush and cleaning cloth to remove all the dirt from the carburetor. Once this is done, you can take a look at the carburetor ports. These are the internal holes/passages within the carburetor. The ports are usually about the same size as the straw attachment of the cleaner. So, place the carb cleaner into the ports and give them a quick spray. The force of the spray normally shoots out any dirt.
The next step is to clean all the small parts you removed from the carburetor. Again, give them a good clean with the brush and the carburetor cleaner. Then, use your small wire and clear out any blockage in the jet. This is the main area that causes problems with the carburetor, so be sure to get the jet completely clear.
Optional Stage – I mentioned a carburetor repair parts kit in the list above. This kit you can get for your carburetor includes items like washers, o-rings, and gaskets. With this kit, you can replace all the perishable parts of the carburetor and thoroughly clean your carb. So if you decide to use a repair kit, be sure to remove the old parts from the carburetor.
Rebuilding the Carburetor
Now that you have the carburetor all cleaned up, it’s time to put it back together. As long as you install all of the parts you removed. So, to rebuild the carburetor, follow the list below in order.
Riding Lawn Mower Carburetor Cleaning vs Push Mower: Is There a Difference?
The method of cleaning a carburetor doesn’t really change between a walk-behind lawn mower to a riding mowing. If anything, I’ve found cleaning a riding lawn mower’s carburetor a bit easier because they tend to have better access to it. I don’t have to kneel on the floor like I do when working on a walk behind because it is so low to the ground. Once I finish my homemade mower table, this won’t be a problem anymore. So, if you’re able to elevate your push mower, then I would say cleaning the carburetor on a riding lawn mower is the same as cleaning a push mower’s carburetor.
I’ll be the first to put my hand up for a simpler way to clean a carb, but not if it’s less effective. Cleaning a lawn mower carburetor without removing it is an option you can use to clean out any fuel gum residue from bad fuel.
You’ll find that this method solves a lot of the problems associated with a bad carb, like getting rid of a sticking float or a restricted jet. But if you struggle with access to the carburetor or blocked carb ports, I’d recommend removing the carburetor completely. Products like carburetor spray cleaners do a good job, but not when it comes to a chunk of grass in the jet. If you try the spray cleaner, but it doesn’t fully solve the issue, you will probably get better results by removing the carburetor and cleaning it thoroughly.
About Tom Greene
I’ve always had a keen interest in lawn care as long as I can remember. Friends used to call me the “lawn mower guru” (hence the site name), but I’m anything but. I just enjoy cutting my lawn and spending time outdoors. I also love the well-deserved doughnuts and coffee afterward!
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Does Carburetor Cleaning Spray Work?
Carburetor cleaning spray is effective depending on the problem you’re dealing with. When you use a carburetor cleaning spray, you only clean one section of the carburetor, which includes the throttle valve, throttle opening, and the jet. So, if the problem lies within this section of the carburetor, then a spray will work. But if the issue with your carburetor is before this area, say, a sticky fuel float or a blockage in the jet, then a cleaning spray won’t work.
To tackle these kinds of problems, you’ll need to remove the fuel cup and address the issue directly. Or, if you’re dealing with a blockage in the carburetor jet, you’ll have to remove the jet from your mower and clean it by hand, as I explained in method 1.
Adjusting The Air And Fuel Mixture
The carburetor controls the amount of compressed air and fuel that enters the engine, and the right mixture is essential for optimum performance.
If the mixture is too rich, it will cause the engine to run excessively rich, resulting in reduced power and efficiency. If the mixture is too lean, it can cause pre-ignition, which can damage the engine. The ideal mixture is about 14.7 parts air to 1 part fuel.
To adjust the mixture, you will need to adjust the screws on the side of the carb.
Start by turning both screws counterclockwise by 1/8 turn. If the engine slows down, turn both screws another 1/8 turn. Repeat this process until you reach the desired mixture. With a little practice, you will be able to fine-tune your carburetor and keep your lawn mower running like new.
Store The Lawn Mower Carburator In A Dry Place
To avoid small engine problems, be sure to store your mower in a dry place where the carburetor won’t be exposed to moisture. Also, use a cover to protect from the elements.
By following the above-mentioned tips, you can keep your lawn mower’s carburetor in good working condition and extend the life of your mower. Be sure to clean the carburetor regularly, adjust the air and fuel mixture as needed, and store your mower in a dry place.
About your guide: Jamey Kramar is a certified Lawn Care Manager (NALP) and a Mechanical Engineer by trade. He has been writing about outdoor power equipment for 11 years and has been quoted in NYTimes, Popular Mechanics, HowStuffWorks, iFixit, Realtor.com, and more. He spends his spare time disassembling things and also building an off-grid cabin at his 200-acre property.
Where is the Carburetor on a Lawn Mower? (every mower)
Do you need to do some troubleshooting or maintenance with your lawn mower? If so, you’ve probably wondered where the carburetor is on a lawn mower. The location of this component of your mower’s engine can vary depending on the type of lawnmower you have.
In today’s article, I’ll tell you what a lawn mower carburetor looks like, where it usually is found on every type of mower, and provide a list of cleaning tips to maintain your mower’s carb.
All About the Lawn Mower Carburetor
What it Looks Like, What Parts of the Mower it Connects to, and
The carburetor is an essential part of your lawn mower’s engine. It makes sure that the correct combination of fuel and air will go into the engine cylinder. This is essential for combustion to occur.
When the spark plug ignites the fuel and air mixture, it combusts and pushes the engine piston in a downward direction. This, in turn, rotates the crankshaft. This makes the lawn mower blade spin.
Depending on the type of lawn mower you have, the wheels of your mower (for example, a riding mower or self-propelled mower) will also start to rotate.
How to Find and Identify Your Mower’s Carburetor
The carburetor is part of the mower’s engine. Typically, it is bolted to the side or top of the engine. It is also connected to the gas tank, and will typically be located just below or behind your air filter. Most lawn mower manufacturers make the air filter housing easily accessible and easy to identify so that owners can change out the filter as part of their annual maintenance. Find the air filter and your mower’s carburetor will be the next part of your mower’s engine, right behind it.
While the location will vary by manufacturer, there are a few qualities most carbs share to make them easier to identify.
Carburetors are metal and rectangular in shape. Your mower’s carb will often have black areas, such as a black circle and trim on the right and left.
In this article I’ll walk you step-by-step through locating and servicing your mower’s carburetor, with specific tips for locating the carburetor on every type of lawn mower.
Different Kinds of Lawnmower
In this section, we will go over the different kinds of lawnmower and where you can usually find the carburetor in each. The two main kinds of lawnmower are walk-behind and riding.
Walk-Behind Mowers
There are four main types of walk-behind mowers, which I list below – if you own a walk-behind mower make sure you know which type it is so that you can refer to the correct part of this article to locate your mower’s carburetor:
Carburetor Location in Walk-Behind Mowers
For walk-behind mowers, you will find the carburetor at the side of the mower, in the area above the base of the mower. As we mention later, the carburetor is connected to the air intake and air filter of the mower. Therefore, finding these components makes it easy to find the carburetor.
If you’re having trouble finding them, search for square-shaped or round-shaped filter housing. This will generally be on the side of the mower’s engine, though it’s sometimes on the top.
The air filter case is usually plastic and pops open easily to provide easy access to the filter for maintenance. The mower’s carburetor is just behind the air filter’s housing, and there are typically 2-3 bolts that can be loosened to remove the filter housing and reveal the carb.
This video does a nice job demonstrating the removal and cleaning of the carburetor on a walk-behind mower:
The exact process for repairing or replacing a carburetor in a riding mower will depend on your exact model, and it tends to be more complicated than working with the carburetor of a walk-behind mower, so you may choose to hire a professional at a small engine repair shop to do this for you.
If you are going to do a carb repair or replacement yourself, my advice is to consult the manual that came with your machine, and document every step of the process so that you can remember how the carb was set up and have an easier time re-attaching everything properly.
Here’s a video from Sears that walks you through replacing the carburetor on a Craftsman Mower. It provides a good sense of what’s involved in this project, what your riding mower’s carburetor looks like, and where the carb is located on some riding mowers:
Why is it Important to Clean Your Lawn Mower’s Carburetor?
The carburetor of your lawn mower needs to be kept clean in order for the machine to work as it should.
Think of the carburetor in a car. If it isn’t kept clean and properly maintained, your vehicle will not run properly.
This is the same with a small engine such the kind you have in a lawn mower.
If you are having certain problems with your mower, there is a good chance that you need to clean the carburetor. Below are some signs of a dirty carburetor:
How to Clean a Mower Carburetor Once You Locate It
Let’s take a look at how to clean a lawn mower carburetor.
Please note that these are general instructions and you should consult with the instructions that come with your particular mower before you proceed.
Removing the Carburetor
What if the Carburetor Needs Repairs?
It is possible that your carburetor will need repair as well as cleaning. If that is the case, you can consider buying a carburetor repair kit. This will help you with replacing some of the major components of the carburetor, such as the diaphragms, gaskets, float, and float needles. You can probably find a kit that matches your mower on Amazon for less than 20.
If you find that the carburetor continues to have poor performance, it’s possible that you will have to get a new carburetor and replace the old one. The price of a replacement carburetor will typically be about 50, and you can find genuine manufacturer’s carb replacements on Amazon (like this one for a Honda self-propelled mower).
If you’re sure your lawn mower issues are the result of carburetor problems, it’s generally easier to buy a new carb and replacing the whole thing vs attempting to repair a few gaskets or parts.
In my experience a repair kit works better in theory than in practice, and your average weekend warrior is better off replacing the whole thing if determined to DIY a fix. For 30 more, why not install a brand new carb?
The other option (recommended for most people) is to take your mower to a small engine repair shop and let them do the work for you. This is less expensive than you’d think, and will save you some time and headaches.
For optimal lawn mower maintenance, you should clean the carburetor every year.
This will help your mower always perform at the optimal level and help to hold off problems that will require parts replacement or full replacement of the carburetor.
And you don’t have to take your carb out to keep it running like new – I give my mower a shot of Gumout Carb and Choke Cleaner (Amazon link) before every mow to keep it running like new. It’s like 5 a can and lasts a whole season.
Maintain Your Lawn Mower So It Lasts!
Understanding how your lawn mower works and how to maintain it is key to making it last.
Purchasing a new lawn mower is an investment, so it’s well worth taking the time to read the manual and understand all the components and their functions.