How To Adjust Lawn Mower Carburetor (Find Out)

If you have a gas-powered lawn mower, chances are that at some point in time you may need to adjust the carburetor. 

This is something that pretty much every owner of a gas-powered lawn mower needs to do from time to time, so there’s no reason why it should be too difficult!

In this article, we’ll walk through how to perform this task so you can feel confident doing it yourself.

Carburetor Adjustment – Everything You Need to Know
Adjusting lawn mower carburetors require proper knowledge and tools
Regular carburetor maintenance is essential for optimal engine performance
Carburetor adjustments frequency may depend on usage, age, and maintenance
Proper diagnosing of carburetor issues is crucial before any adjustment
Seeking professional help is recommended for more complex carburetor problems

Turn Off The Mower

Before you pull out your carburetor, you’ll want to make sure the machine is turned off and in a safe place. 

The mower should not be running or plugged in when working on it; also, if the lawn mower is on a slope, do not adjust the carburetor until it is flat.

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Take Off The Air Filter Cover

  • Remove the air filter cover by unscrewing it.
  • Take off the air filter and carburetor adjusting screw, then remove any screws that are holding down the carburetor to the engine.
  • Locate the idle mixture screw and turn it counterclockwise until it will not turn any further.
  • Tighten all of your screws, replace everything you removed from the carburetor, and put back on all covers over your engine before starting up again!

Steps for Removal of Air Filter Cover and Cleaning

Turn off the lawn mower to avoid accidental startup
Locate the air filter cover, usually located near the top of the engine
Unscrew or unlatch the cover to remove it
Take out the air filter, and check for damage or dirt accumulation
Clean the air filter by tapping it on a surface or using compressed air
For caked-on dirt, cleaning with water or mild soap is recommended
Dry the air filter before putting it back and reassemble the cover
Make sure all parts are securely in place before restarting the lawn mower

Remove The Air Filter

To remove the air filter, you’ll need to disassemble the cover over the carburetor. The cover is held on by one or two screws, depending on your mower’s model. Remove these and set them aside.

To access the air filter, simply lift off the top of your mower’s engine compartment (where all of your other maintenance items are located). 

If it’s tough to pull up, try pressing down on any levers inside that might be keeping it in place.

Once you’ve gained access to this area of your mower, locate the air filter and clean or replace as needed this can be done once per season or more often if you’re cutting the grass regularly and/or in hot weather conditions where dust tends to collect more quickly than usual.

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Find The Screws On The Carburetor

Now it’s time to locate the screws on your carburetor. Your carburetor is at the top of your engine, and there are several screws visible from here. 

The idle mixture screw is located toward the front of the carburetor and closest to your throttle lever. 

There are two other screws that can be used for adjusting one on each side of this one but these do not need to be adjusted unless you have trouble starting or running due to an over-fueling problem (too much fuel entering your engine).

Steps in Finding Screws on Lawn Mower Carburetors

Turn off the lawn mower and let the engine cool down
Locate the carburetor, typically located on the side of the engine
Depending on the model, there may be one or more screws found on the carburetor
Look for screws labeled with “L,” “H,” or “T” for low, high, and idle speeds, respectively
Identify which screw is for the idle speed adjustment by checking the model manual
Use a screwdriver to gently turn and adjust the screw as needed
Keep track of the number of turns made or adjust to factory specifications
Test the engine’s performance by restarting the lawn mower and observe for any improvements

Locate The Idle Mixture Screw And Turn It Counterclockwise Until It Will Not Turn Any Further

The idle mixture screw is located on top of the carburetor. It controls how much fuel flows into the engine when it’s idling, but you’ll want to adjust this screw before attempting to work on anything else.

To find it, start by removing your mower’s air filter and then pulling it up on its hood (or canopy). You should see two lines: one running from left to right across the center of the carburetor, and another running front to back along its side. 

The line that runs front-to-back will likely have red markings indicating what each section should look like but we recommend ignoring those for now! 

Instead, focus on finding a small silver knob with an arrow pointing down towards it; this is your idle mixture screw. 

Once you’ve found this part, turn counterclockwise until you can’t turn any further then turn clockwise until there’s no resistance at all before turning back counterclockwise again (and repeating until there are no more adjustments).

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Turn The Idle Speed Back To Where You Set It Earlier If Needed

Once you’re done, turn the idle speed back to where you set it earlier, if needed. It should be at the same place that it was when you started.

Put The Air Filter Back In Place And Replace The Cover

Once you’ve adjusted the carburetor, check that it is idling smoothly without the choke opening or closed. If not, repeat these steps until it does.

If you’ve successfully adjusted your mower’s carburetor to run properly and are happy with your work, congratulate yourself on a job well done!

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Start Your Mower And Give It A Few Minutes To Warm Up

Start your mower and give it a few minutes to warm up. The engine will idle at a higher speed when it is cold, so the carburetor may need adjustment once all the air has burned off and settled into its seat.

Once your mower is ready to go, you can adjust the carburetor according to our guide below:

Check To See If It Is Idling Smoothly Without The Choke Opening Or Closing

Next, you’ll want to check your lawn mower’s idling. Does it idle smoothly with the choke open and closed? If it does not, this may be an indication that your carburetor needs adjustment.

You’ll also want to observe how the engine responds when you accelerate and decelerate (if you can do so safely). Is there a delay before power is applied? If so, this could be another sign of a clogged or improperly adjusted carburetor.

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Move Back And Forth To Test How Well It Is Running At Different Speeds. Make Adjustments If Needed

Once you have made your adjustments, you can test how well the lawn mower is running. Move back and forth to see if there are any problems with any speeds.

 If an adjustment needs to be made, simply make it and retest the speed of the engine at each position.

Make sure that you check all of your settings before starting up a new mower or using an old one that has been sitting for a while. 

If there is anything wrong with them, they could cause damage to your engine or other parts of your machine. You should take care when adjusting carburetors so that no harm comes to yourself or anyone else who may be around when working on it.


Congratulations! You’re now officially a carburetor expert, and you have the tools to tackle any future carburetor issues that may arise. So when it comes time for you to adjust your carburetor, consider these tips before starting. 

First off, make sure that you have all of the right tools on hand especially if this is your first time adjusting a carburetor or rebuilding one from scratch. 

Secondly, make sure that your engine is in good working order before making any adjustments; otherwise, they won’t be worth much at all! 

Finally and most importantly don’t forget about safety precautions: wear protective clothing when working around gasoline and other flammable materials like grease or oil. And remember: always keep children away from open engines until they are safely put away again!

Further Reading

For more information on how to adjust lawn mower carburetors, check out the following resources:

Adjusting a Riding Mower Carburetor: A comprehensive guide on adjusting carburetors on riding mowers.

How to Adjust the Carburetor on a Briggs and Stratton lawnmower: Step-by-Step: A step-by-step guide on adjusting carburetors specifically on Briggs and Stratton lawnmowers.

Adjusting Lawn Mower Carburetors: An informative article on adjusting carburetors on various types of lawn mowers.


What is a carburetor, and why is it important for lawn mower maintenance?

A carburetor is a key component in a lawn mower’s engine that’s responsible for mixing air and fuel to create combustion. It’s essential to maintain the carburetor to ensure optimal engine performance.

How often should I adjust my lawn mower’s carburetor?

The frequency of carburetor adjustments depends on various factors such as age, usage, and maintenance. It’s recommended to inspect and adjust the carburetor at least once a year.

What symptoms indicate that my lawn mower’s carburetor needs adjustment?

Signs of a faulty carburetor include irregular engine idling, decreased engine power, and stalling during operation.

Can I adjust my lawn mower’s carburetor myself?

Adjusting a carburetor may sound intimidating, but it’s doable with proper knowledge and tools. However, it’s still advisable to seek professional help when dealing with more complex issues.

What are the basic steps in adjusting a lawn mower’s carburetor?

The basic steps in adjusting a carburetor are identifying the adjustment screws, turning them according to factory specifications, and testing the engine’s performance. Proper sequence and procedures may depend on the type and brand of lawn mower you have.