Pro Tips for Cleaning a Lawn Mower Carburetor

Start Your Engine (At Least Try)

• Confirm that the fuel valve is on, there’s gas in the tank and the spark plug is in good shape.
• Shoot a one-second burst of aerosol lubricant or carburetor cleaner down the throat of the carburetor.
• Then, yank the cord.
  • Note: If the engine runs (even just sputters) and dies, you have a fuel problem. If there’s no life after a few tries, it’s something more serious and you need to haul the engine to your garage for some detective work.

A hand in a glove holds a dirty carburetor, while a red lawn mower is disassembled on a wooden surface, surrounded by tools and a spark plug.

Test for Gas at the Lawn Mower Carburetor

• Clamp off the fuel line.
• Compress the spring clamp and slide it backward on the fuel line.
• Pull the tubing off the carburetor nipple and catch the gas in a small bowl.
  • Note: If no gas comes out of the fuel line, you’ve got a plugged fuel line or fuel filter.

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Remove the Lawn Mower Carburetor

• Use a socket or nut driver to remove the two bolts that hold the carburetor to the engine.
• Unhook the throttle cable from the carburetor linkage.
• Place the carburetor in a container (to catch the gas).

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Check for Corrosion

•  Open the carburetor bowl to check for corrosion.
  • Note: If the inside of the carburetor is corroded, it needs to be replaced. Even after cleaning, the corrosion will clog the jets and tiny orifices and restrict the flow of gas.

4

Rebuild or Replace?

If there’s no corrosion in the carburetor, you can choose to rebuild it rather than replace it. But rebuilding isn’t always cheaper, and it might not even do the trick. Sometimes you can buy a new carburetor for less than (or pretty darn close to) the cost of the rebuilding kit plus the cost of the chemicals. We always just replace bad carburetors rather than rebuild them.

If you opt to rebuild, follow the steps below:

Dissect the Lawn Mower Carburetor on Your Workbench

• Start the disassembly from the bottom (bowl, float, needle, seat, etc.) and keep all the parts together.
  • Pro tip: Shoot photos for help during reassembly.
• Match the new gaskets and O-rings in the carburetor repair kit to the old ones.
• Set aside the used gaskets and O-rings you’ll discard, and any parts from the kit you don’t need.

5

Clean the Parts

• Wire all the larger parts together and drop them into a bucket of carburetor cleaner.
• Then, wrap the small parts in a piece of aluminum screen or use a fine-mesh basket, and drop them in the bucket as well.
  • Note: New/replacement parts don’t need to be cleaned.
• Let the parts soak for one hour.

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Reassemble the Lawn Mower Carburetor

• After the hour is up, rinse all the parts with water and blow them dry with compressed air.
• Reassemble the old and new carburetor parts and then mount it on the engine.
• Follow the instructions in the kit for adjusting the idle speed and mixture.
• Finally, fire up your engine and listen to it purr!
• Congratulations, you’ve fixed your carburetor without having to google “small engine repair near me.”

FAQ

When should I consider professional repair?

If after applying aerosol lubricant or carburetor cleaner down the throat of the carburetor there’s still no engine life after a few tries, it’s time to bring it to a shop for professional repair.

Can I clean the carburetor without removing it?

Remove the carburetor bowl, then apply carburetor cleaner to the fuel passages and bowl to clean without removing the carburetor completely.