How to replace a lawn mower carburetor

This step-by-step lawn mower repair guide gives instructions for replacing a lawn mower carburetor. The carburetor blends air with fuel to form a combustible mixture that ignites in the cylinder to drive the piston. If the carburetor is clogged or damaged, the engine runs rough or won’t start. If the carburetor is clogged or damaged, replace it with a manufacturer-approved lawn mower part.

Use these steps to replace the carburetor on common Briggs & Stratton engines that power Craftsman, MTD, Husqvarna, Poulan, Murray, Toro, Troybilt and Ariens walk-behind lawn mowers. If you'd rather rebuild the carburetor, How to Rebuild a Lawn Mower Carburetor shows you how.

Instructions

1. Disconnect the spark plug wire

Working in a well-ventilated area, disconnect the spark plug wire from the spark plug.

2. Remove the air filter housing

Release the catch and pull the air filter cover off.

Remove the air filter.

Remove the screws from the air filter base.

Release the breather tube and pull off the air filter base.

3. Drain the fuel tank

Place a shop rag under the fuel tank to catch spills.

Place a fuel-safe container under the gas line connection to the fuel tank.

Release the spring clamp and disconnect the fuel line from the gas tank.

Drain the gasoline into the container.

Wipe up any spills.

4. Remove the blower housing

Release the starter rope from the mower handle.

Remove the screws from the blower housing.

Pull the blower housing off the engine.

5. Remove the carburetor

Separate the carburetor mounting bracket arms to release the carburetor and disconnect the carburetor from the carburetor adapter.

Holding the carburetor above the bracket, disconnect the governor and choke linkage rods and remove the carburetor.

Release the fuel line spring clamp and pull the fuel line off the carburetor.

6. Install the new carburetor

Push the O-ring into the outlet port of the new carburetor.

Install the retainer on top of the O-ring.

Connect the fuel line to the new carburetor and secure it with the spring clamp.

Hold the carburetor over the mounting brackets and connect the governor and choke linkage rods.

Push the carburetor into the bracket arms and push the outlet port fully onto the carburetor adapter.

Push the air cleaner gasket into the channel on the carburetor inlet.

7. Reinstall the blower housing

Position the blower housing on the top of the engine and line up the mounting holes.

Reinstall the blower housing mounting screws.

Reconnect the starter rope to the mower handle.

8. Reconnect the fuel line to the tank

Push the fuel line onto the tank fitting and secure it with the spring clamp.

9. Reinstall the air filter housing

Position the air filter base on the front of the carburetor and reconnect the breather tube.

Secure the air filter base with the mounting screws.

Reinstall the air filter.

Position the air filter cover on the front of the base and snap it into place, engaging the locking tab.

10. Reconnect the spark plug wire

Push the spark plug wire back onto the spark plug.