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 replacement 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.
This video explains how to replace the carburetor on a walk-behind lawn mower.
Disconnect the spark plug wire
Working in a well-ventilated area, disconnect the spark plug wire from the spark plug.
Disconnect the spark plug.
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.
Pull off the air filter base.
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.
Drain the gasoline.
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.
Remove the blower housing.
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.
Remove the carburetor from the lawn mower.
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.
Install the new carburetor.
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.
Reinstall the blower housing.
Reconnect the fuel line to the tank
Push the fuel line onto the tank fitting and secure it with the spring clamp.
Reconnect the fuel line to the tank.
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.
Reinstall the air filter base.
Reconnect the spark plug wire
Push the spark plug wire back onto the spark plug.
These step-by-step repair guides will help you safely fix what’s broken on your walk-behind lawn mower.
Replace the ignition coil if it isn't sending electric current to the spark plug when you pull the recoil starter rope.
The flywheel key couples the flywheel to the engine crankshaft. Replace the flywheel key if it's broken.
The drive cable engages the transmission to spin the drive wheels and move the mower across the grass. Replace the drive cable if it's broken or frozen up inside the sheath.
Use the advice and tips in these articles and videos to get the most out of your walk-behind lawn mower.
See how to tune up your mower once a year to keep it running well.
Do these 5 things this spring for a lawn that's healthier all summer.
Prevent your mower deck from rusting by following our advice for keeping grass clippings from sticking.