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How to change a lawn mower carburetor?

A carburetor is the core element that keeps your Lawnmower running strong and perform better. The lawnmower carburetor ensures that the proper mixture of fuel and air will enter the engine cylinder for combustion. When ignited by the spark plug, the fuel and air mixture will combust, forcing the engine piston downward, which rotates the crankshaft causing the lawnmower blade to spin and the lawnmower wheels or riding mower wheels to turn.

The most censorious component for the functionality of a Lawnmower is the carburetor. If the carburetor is clogged with dirt, it has water damage, debris, gummed-up gasoline, rough engine running, running rich, stalling, and many other problems. Replace a damaged or restricted riding lawn mower carburetor with a manufacturer-approved replacement part.

If the carburetor is not beyond repair, you can rebuild it instead of replacing it.

How to change a lawn mower carburetor?

For your Lawnmower’s smooth working, follow these steps to replace a carburetor yourself without calling in a professional.

  • Step 1. Unhook the wire within the spark plug.
  • Step 2. Bring out the air filter housing.
  • Step 3. Drain the fuel tank.
  • Step 4. Remove the blower housing.
  • Step 5. Remove the carburetor.
  • Step 6. Install the new carburetor.
  • Step 7. Restored the blower housing.
  • Step 8. Attach the fuel lines to the tank.
  • Step 9. Reinstall the air filter casing.
  • Step 10. Affix the spark plug wire.

Steps To Follow:

The steps mentioned above will undoubtedly help you get familiar with mechanical components and save your time and cash. Do not worry, as we promised; we would discuss every step individually.

● Step 1. Unhook the wire within the spark plug:

Firstly, you have to disengage the primary spark plug wire. Probably the most important safety precaution that you can take when doing your repairs or maintenance on a lawnmower is to disconnect the spark plug wire before you do anything else.

Merely follow these simple for the segregation of ignition wire. Disconnect the spark plug. Then, remove the rubber “boot” that connects the spark plug to the wire. In the end, make sure to turn it, so the back of the boot is facing the spark plug.  Another prime concern is that you must be working in a well-ventilated area to prevent any property and self-damage.

● Step 2. Bring out the air filter housing:

Secondly, you have to detach the air filter casing. Then, unbolt the screws and pull the air filter cover off. After that, take out the air filter. At that moment, unfasten the screws from the base of an air filter.  Lastly, release the breather tube, and then last but not least, pull off the air filter base.

● Step 3. Drain the fuel tank:

Next, you have to drain the gas tank. First, place a shop rag or piece of cloth under the fuel tank to catch the dribbled out fuel. Then, place a fuel-safe container under the gas line connected to the fuel tank. Farthest away, release the spring clamp and separate the fuel line from the gas tank. This is how you drain the gasoline into the container. For cleanliness during your work, it is better to wipe up any fuel drizzles promptly.

● Step 4. Remove the blower housing:

Then, disengage the outer blower casing. The following steps will help you to disengage the casing. At first, you have to dispatch the starter rope from the main handle of the mower. Afterward, unfasten the screws from the outer blower casing, and the next step is to take off the engine’s blower housing.

● Step 5. Remove the carburetor:

It is recommended that you record a video during this procedure or take some photos of the assembly after every step to be easy for you to install the new one on the same procedure. 

Firstly, separate the carburetor mounting bracket arms to release the carburetor. Carefully disassemble the screws and jets. Now, disconnect the carburetor from the carburetor adapter. Then, grasp the carburetor above the bracket and disconnect the main lines that govern the carburetor’s functioning. At that point, remove the choke linkage rods, remove the carburetor, and then release the fuel line with a spring clamp.  Last in order, pull the fuel line off the carburetor.

● Step 6. Install the new carburetor:

Initially, push the O-ring into the outlet port of the new carburetor. Then, install the retainer on top of the O-ring. Now, Connect the fuel line to the new carburetor and secure it with the spring clamp. You have to hold the carburetor over the mounting brackets, connect the governor, and choke linkage rods. Later, push the carburetor into the bracket arms and fully push the outlet port onto the carburetor adapter. In the end, push the air cleaner gasket into the channel on the carburetor inlet.

● Step 7. Restore the blower housing:

Reconnect the blower housing by following the steps below:

  • Step 1: Set the blower housing on the top of the engine and line up the mounting holes.
  • Step 2: The blower housing mounting bolts and screws must fit tightly to maintain the balance of the whole assembly.
  • Step 3: Re-join the starter rope to the handle of the mower.

● Step 8. Attach the fuel lines to the tank:

Push the fuel line onto the tank fitting and secure it with the spring clamp. It would be best to be cautious in connecting the fuel lines so that no fuel leakage occurs.

● Step 9. Reinstall the air filter casing:

The following steps will help you to reconnect the casing of the air filter.

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.

● Step 10. Affix the spark plug wire:

Push the spark plug wire back onto the spark plug. The whole assembly is back in its original position. Now it’s time to run your mower to check whether the system functions up to the mark.

Frequently asked questions:

1. How do I know if my lawnmower carburetor is terrible?

Some symptoms are showing that your carburetor is full of dirt, dust, and debris.

  • The lawnmower engine has trouble starting.
  • The engine starts but stalls while you are cutting the lawn.
  • The engine runs rough during mowing.
  • Black smoke is seen coming out of the muffler.
  • There is a noticeable increase in fuel consumption during everyday lawn mower use.

2. Can you clean a carburetor without taking it apart?

You can clean the outside of the carburetor without disassembling it, but the critical stuff to clean is on the inside, and for that, it must be disassembled not all the parts but the outer casing at least. Buy a good quality carb cleaner that is an aerosol spray. Clean all of the passages thoroughly with it. This is how, without removing the carburetor, you can clean your dirty, dusty and carburetor with old grass and debris.

3. Is it better to rebuild a carburetor or buy a new one?

In my opinion, it is better to rebuild a carburetor rather than replacing it. The internal parts like spark plugs, choke linkages, fuel lines, and head gaskets maybe weakened and crumble, which in return cause multiple problems. Besides, the gas that sits in the fuel bowl can deteriorate and start to vanish parts inside the carburetor. So it is recommended to replace only the defective parts timely. Some replacement carburetors cost $400 to $600.

Final Remarks

A carburetor ensures that the air-fuel mixture in the appropriate proportion is supplied to the engine that ignites in the cylinder to drive the piston. Like all other devices and machinery, timely care and maintenance of mowers can prevent any major or critical issues. The tuning and cleaning of vital parts are recommended timely. In severe cases, defective parts must be replaced well in time to prevent the abruption in the mower system. Proper maintenance and preventive measures enhance the life of the components, their functionality, help our machine work properly, prevent corrosion, and save costly replacements. Its care decides whether our Lawnmower will provide service for years or fizzles early. If you find that your current Lawnmower’s repairing and maintenance will be expensive, you should better invest more and get yourself a new lawnmower.