Lawn Mower Carburetor Maintenance Tips – Step By Step Guide

Today you’re going to learn how to save a lot of money.

How?

By learning how to perform your own maintenance on the lawn mower carburetor.

Cleaning the carb is easy and a less than 1 hour job to save you $100s of dollars a year.

First up, you’ll see a quick-guide on how to remove your carburetor for cleaning (and how to clean it). Then we’ll go into more detail about the carb and what it does and why maintaining it is important.

Okay, let’s do this.

Carb Maintenance – 10 Quick-Steps

Most issues related to starting your lawn mower can be blamed on the carburetor. Specifically, fuels left sitting in the carb over time gumming up and creating flow problems.

  1. To start: find and remove carburetor from lawn mower (you may have to remove some parts to get to it – it will usually be behind the air filter). Be sure to clamp off the fuel line before removing.
  2. With the carb removed pull the gaskets away and look for damage – replace if necessary.
  3. Initially clean exterior with a spray carb cleaner you can buy from any hardware store.
  4. Remove the carb bowl – be careful as regular gasoline will still be present. Have a plastic container below.
  5. With the bowl off you have access and can start to disassemble the flow and metering needle. Now, remove the screw holding the main jet to pull apart. Now remove the emulsion tube in the carb head. And finally remove the round seal gasket from the outside diameter (replace with new gasket).
  6. Remove the idle screw to get access to the screw covering the pilot kit (see video for visual of which screw is which).
  7. With everything disassembled you can clean the internals of the carb with the carb cleaner. If you have access to an ultrasonic cleaner use that as well.
  8. Now go through and clean all the parts you pulled apart from the carburetor.
  9. Put everything back together. Be sure there is no residue left from the old gaskets – if there is remove with a knife blade.
  10. Install carb back onto lawn mower and re-install the fuel lines and air filter/cover.

Watch the carb cleaning video for visual directions:

Now let’s look at the lawn mower carburetor in more detail.

How a Lawn Mower Carb Works

They are tasked with mixing fuel and air together before sending it to the engine. Gasoline is flammable, so it needs to be carefully combined with air before it can be used as fuel. The carb has a number of small parts that work together to create the ideal mixture of fuel and air.

The carb bowl holds a small amount of gas, which is then drawn up into the throat by the action of the diaphragm. The diaphragm is connected to the engine’s intake valve, which opens and closes to allow air into the engine. When the diaphragm moves, it also opens a small port that allows gas to flow from the bowl into the throat. As the gas flows through the throat, it mixes with incoming air and is drawn into the engine. Carburetors are fairly simple devices, but they play a vital role in ensuring that lawn mowers run smooth and efficient.

The Importance of Maintenance

Like any machine with moving parts, a lawn mower requires regular maintenance to keep it running smooth. One of the most important parts of a lawn mower is the carburetor. It controls the mixture of air and fuel that is delivered to the engine, and over time, it can become gummed up or out of adjustment. If you notice that your lawn mower is struggling to start or running rough, it may be time to clean or adjust the carb.

Fortunately, this is a relatively simple process.

Step By Step Guide: Lawn Mower Carb Maintenance Tips:

Check The Air Filter

A dirty air filter can restrict airflow to the carburetor, causing the engine to run lean. Lean engines run hot and can damage other engine components. Check the air filter regularly and clean or replace it as needed.

Clean The Fuel Tank

Over time, the fuel filter can become filled with dirt and debris. This can clog the fuel line and prevent the carburetor from getting the gas it needs to run properly. Drain the tank and clean it out regularly to prevent this problem.

Inspect The Spark Plug

A fouled or damaged spark plug can cause starting and running problems. Inspect the spark plug regularly and replace it as needed.

Check The Carburetor

The carburetor can become gummed up with dirt and debris, causing starting and running problems. Clean the carburetor periodically to keep it in good working condition.

Clean The Lawn Mower Carburetor

Over time, the carburetor can become clogged with dirt and debris, which can prevent the engine from running properly. Therefore, regular cleaning is important. There are several ways to do this, but one of the most effective methods is to use a spray-on cleaner.

  • First, remove the air filter cover and spark plug from the engine.
  • Next, spray the carburetor cleaner into the carburetor and dirty spark plug. Then allow it to soak for several minutes.
  • Finally, use a brush to scrub away any remaining dirt and debris.

By following these steps, you can keep your lawn mower running smoothly for years to come.

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.

Wrapping Up:

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.

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About your guide: Jamey Kramar is a certified Lawn Care Manager 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.