How to clean a Briggs and Stratton lawnmower carburetor, step by step


For any machine that has a gas engine, the carburetor is one of the crucial components. The machine’s lungs supply a suitable air-fuel mixture to the combustion chamber, keeping the lawnmower robust and healthy. If your Briggs and Stratton lawnmower has been used for an extended time without proper service, the first component to show problems is the carburetor. If you use your mower in a more harsh environment, dirt and debris can reach the carburetor and other components like the air filter, air channel, and fuel lines. A dirty carburetor can cause problems like engine power reduction, weak performance, and smoking issues. If you experience those problems, you need to clean the carburetor.

Cleaning the carburetor is not as complicated as it may seem. People generally take it to the repair shop, but you can do this yourself at home, and it should take around an hour. This article describes the steps that are needed to clean a Briggs and Stratton lawn mower carburetor.

How to clean a Briggs and Stratton lawnmower carburetor, step by step:

  • Step1. Remove the outer casing of the engine.
  • Step 2. Check the Air Filters and their housing.
  • Step 3. Unbolt the carburetor
  • Step 4. Clean the carburetor bowl.
  • Step 4. Clean the central gasket and check all connections in parallel.
  • Step 5. Use a Carburetor Cleaner.
  • Step 6. Reassemble and reattach.

Cleaning a Briggs and Stratton lawnmower carburetor:

The following steps will unquestionably help you get familiar with mechanical issues you have to deal with, along with the issues you might face. Do not worry, as we assured; we would discuss every step discretely.

● Step 1: Remove the outer casing of the engine:

Park the lawnmower on a hard surface that can deal with gas spillage. Before starting with the carburetor cleaning, you should first disconnect the spark plug cables. This ensures that the engine can not unintentionally start. Close the fuel valve so that no gas can escape from the tank. If your mower does not have it, you should remove the gas from the tank. After the gas supply has been stopped, remove the casing from the engine compartment. This should reveal the Briggs Lawn mower’s engine.

Tip: If you are cleaning your carburetor the first time, there is a vital tip; it is suggested that you record a video throughout this practice or take some assembly photographs after each stage. You can reassemble each part back onto its original place using them in the end.

● Step 2. Check air filters and their housing:

Remove the mower’s air filter or the complete housing if you need to clean that as well. The air filter is clipped between two air channels. By removing the clips, you can extract is. For the housing, remove the screws holding on the air filter channel, and pull the housing off. By now, the carburetor becomes noticeable too. Separate the breather tube. The breather tube is part of the crankcase ventilation system and, in most cases, includes a one-way valve that makes sure that exhaust gases are not cycling back into the engine. Please note that not all lawnmowers have a breather tube.

The principal thing is to ensure that the air filter is free of twigs, dirty grass, and debris for cleaning the carburetor. A choked or blocked air filter will produce black smoke visible coming out of the muffler. It will clog the air passage for our carburetor, and thus it cannot “breathe” due to hindrance interference.

● Step 3. Unbolt the carburetor:

The carburetor is fixed on the engine assembly with some mounting bolts. Loosen them with the help of a wrench. Remove the carburetor and carefully detach the fuel lines. Extract the main assembly components. Please be careful while disconnecting the fuel lines as fuel spilling might occur. It is suggested to have some rags arranged to catch the carburetor’s dripping liquid and the fuel lines.

Fuel spilling ensures that your fuel line is clear, unpolluted and hence no fuel blockage is there. If no spilling occurs, your fuel lines may be clogged with debris or from poor fuel. In that case, it becomes necessary to clean them. Fuel lines can be cleaned by a carb cleaner or by running some air pressure through the lines. Please give them a clean fuel bath and let them dry under the Sun.

● Step 4. Clean the carburetor bowl:

We can start now with the carburetor bowl. Use a cleaner spray to clean around the carburetor bowl. A single screw clutches the bowl; unthread that screw to release the carburetor bowl. This nut is a jet with a spore. Check that the hole is clear of any barriers. The hole allows to keep the pressure inside the bowl stable, so you need to clear the hole if it is dirty. This can be done simply by poking a paper clip or piece of wire inside.

Debris inside the jet is one of the most frequent reasons for a carburetor to stop working. It would be best to give the components a proper bath by using some gas and cleaning it with an old toothbrush. Finally, spray some carburetor cleaner on the nut. If the bowl is impaired and has cracks on its edges, you should change it.

● Step 4. Clean the central gasket and check all connections in parallel:

Remove the screws of the bowl to release the prime bulb and base. Detach the components, including the metering plate, diaphragm, and the main gasket packed in the bowl. These are small components closely placed in the bowl. Take a picture to remember the assembly. If the gasket is old or rusty, clean it by scraping it off with sandpaper because this rust might affect the bowl’s functionality. If the gasket is damaged, remove the old one and replace it with a new one.

As an additional step, we recommend checking all the possible connections between choke plates and the carburetor’s throttle. They can malfunction when they become dirty. Suppose your mower is facing performance issues. In that case, this is an additional step you should try. Lastly, the perpetual vibration and abrasion can remove screws, contributing to abnormal handling and auxiliary carburetor problems. If that is the case, it can be a good idea to ask an expert for help.

● Step 5. Use Carburetor Cleaner:

Whenever you are loosening, opening, or cleaning carburetor components, spray some of the carburetor cleaner to help remove the black deposits. These deposits can congest the air and fuel passage, decrease the efficiency, or stop the engine altogether. You can always squirt in a flow of carb cleaner into the air channels while the engine is running.

● Step 6. Reassemble and reattach:

Once the cleaning is completed, reattach the carburetor parts. Use the photographs or video you took to help with that. Start the engine and let it run for a few minutes inhaling the fresh air while exhaling the dirt from its exhaust.

Keep in mind that reattach the parts inside out, i.e., first the bowl components, then the carburetor with the air filter and fuel channel in the end.

Here are some additional tips for cleaning and reinstalling your carburetor:

  1. Dry the carburetor: Initially, allow the carburetor to dry and then reassemble it, ensuring that you properly position the diaphragms, gaskets, metering plate, and primer base required along with the float needle and float.
  2. Arrange the bowl: Ensure the bowl gasket is adequately arranged. Reposition the bowl if necessary.
  3. Reassemble the carburetor: Move the restored carburetor smoothly back onto the mounting bolts and fasten the throttle coupling to the throttle lever.
  4. Attachment of fuel lines: Reattach the fuel line to the carburetor.
  5. Filter casing must be appropriately set: Relocate the air filter casing together with the air filter and filter cover.
  6. Reinstall the outer casing: Reinstall the engine cover if required.

Frequently asked questions:

1. Where do you spray carburetor cleaner on a lawnmower?

Position the aerosol tip can into the middle of the carburetor and spray straight into the working carburetor. After this, the carburetor allows the cleaner to penetrate the carburetor’s body and cleans the carburetor’s throat. Scratch the deposits away that can be seen in the down throttle plate

2. How to clean a gummed up carburetor?

There are four main steps to clean a gummed up carburetor:

  • Step 1: Check the gas condition.
  • Step 2: Drain the gasoline.
  • Step 3: Add B-12 fuel additive.
  • Step 4: Clean the carburetor with the cleaner, as explained earlier in step 5.

3. Should I use water to wash the carburetor internals?

Never use water when cleaning the carburetor components like the bowl and fuel lines. You should always use fuel like diesel or petrol to wash the components. Use an old toothbrush to wipe the debris off. And let the components dry in the Sun. Water can rust the channels and insides, fuel is volatile, so always use that.

Final remarks:

When your Briggs and Stratton lawnmower does not work as it should be, maybe the engine sounds rough, or it has problems starting. In those cases, a dirty carburetor can be the reason. Cleaning a carburetor is not a difficult task and should take up to an hour. During the winter season, the lawnmower is not used. Before using it in the spring, you should check the carburetor and clean it if necessary. This blog post will give you all the steps on how to clean a malfunctioning or dirty Briggs and Stratton carburetor. A properly cleaned lawnmower carburetor can prevent harmful effects like starting problems or stalling issues. And it can enhance your mower life.

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