How to Repair a Lawn Mower Carburetor

Lawn mowers are one of the most used garden tools for maintaining property. Occasionally, problems occur with the engine, making the lawn mower run poorly even with proper maintenance. A common problem is buildup of debris or residue in the fuel. This can block air lines or the carburetor. The blockage will cause the motor to run poorly, increase gas usage and can damage the engine over time. Cleaning the carburetor and related parts connected to it is the best method to solving this problem.

Things You'll Need

• Screwdriver
• Butter tub
• 5-gallon bucket
• Socket wrench
• Gasoline
• Paper towels

Instructions

1. Unscrew the screws on top of the protective engine housing and set these aside in the tub. Lift the housing up and off the engine. Pull the primer bulb cover off. Examine the primer bulb for cracks or leaks. Find the clips that hold the primer bulb in place. Push the clips inward. Use the screwdriver to work the bulb loose to remove it. Examine the housing for cracks or damage; replace the housing if needed.

2. Search for the breather on the carburetor. This is the piece alongside the carburetor. Unscrew the screw holding it in place, using a screwdriver. Remove the breather and set it in the tub with the screws. Disconnect the springs from the mower housing and set these in the tub. Look for the holding bolts around the carburetor; there are either three or four bolts. Use the socket wrench to remove the bolts.

3. Remove the L-shaped tube connecting the carburetor and the engine. This allows the carburetor and gas tank to be removed. Use the socket wrench to remove the two bolts holding the gas tank and carburator together. Notice where the gasket for the gas tank and the spring on the carburator are placed. Put the spring into the tub. Keep the gasket on the gas tank.

4. Fill the bucket 1/4 full with gasoline. Place all of the parts from the tub into the gasoline. Swish around the parts to clean them. The gasoline is abrasive and will break off any residue or debris. You will start to see debris or specks floating. Remove and dry each part. Return the parts to the tub.

5. Examine the screen found on the bottom of the carburetor that slides over the gas intake; replace worn or damaged screens. Fill the bucket halfway with gasoline. Place the carburetor into the bucket until it is submerged. Swish around the gasoline with the stick to clean the carburetor parts. You will see residue and specks breaking loose. Remove the carburetor to examine it. Repeat the cleaning if necessary to remove all of the buildup and remove it from the gasoline again. Dry the carburetor off.

6. Analyze the operation of the choke. It should move without needing to be pushed hard; if it sticks, clean the carburetor again and clean the choke. Examine the choke again. If it still sticks, replace the carburetor.

7. Pour out the old gas into an approved container for gasoline. Put clean gas into the tank; use enough gas to cover the bottom of the tank. Close the gas tank. Shake the tank vigorously; this allows the gas to agitate inside the tank and clean the interior of the tank.

8. Take the top back off of the tank. Empty the dirty gasoline into a container. Examine the tank interior for gunk lining the bottom of the tank. Clean the gunk out with the wire brush.

9. Reassemble the dry carburetor parts in reverse order of how it was taken apart. Put the spring back into place between the carburetor and the gas tank. Attach the two bolts that hold the carburetor and the gas tank together. Place the L-boot back onto the tube. Set the carburetor in position on the engine. Attach the boot to the carburetor. Put the bolts into place that hold the carburetor to the engine. Attach the breather. Tighten down all of the bolts and screws.

10. Start the mower engine. Allow it to run for a few minutes. If the engine stalls or sputters, stop the engine. Repeat the entire process from the beginning. If the engine works fine, stop the engine and reassemble the housing.

Tips & Warnings

• If you purchase a new carburetor, it will come with new springs, so you can toss out the old springs.

• Draining the gas at the end of each year can help prevent this problem.

• Do not attempt to run the mower without the carburetor.

• Do not attempt to clean the carburetor while it is still attached to the mower.

References

• John Middendorf: Middendorf Tractor Sales and Service

Resources

• Read this Article in Spanish