How to clean a Briggs and Stratton riding lawn mower carburetor

Approx Reading Time: 10 minutes

Briggs and Stratton riding lawnmowers are among the best. But, as with all lawnmowers, it is necessary to keep its carburetor clean to work smoothly. This article will give you the steps to clean your carburetor and guidelines on repair and maintenance of your Briggs and Stratton carburetor to keep the engine healthy and keep using it for a long time to come. Before starting any maintenance or overhauling, please ensure to check your Briggs & Stratton operator’s manual. Follow all safety measures and follow this systematic guide to clean a lawn mower carburetor.

A restricted or clogged carburetor becomes a prime cause for a mower to stop operating smoothly. Imposing this cleaning’s significance prevents you from the possible problems caused by the blocked or gummed up carburetor.

How to clean a Briggs and Stratton riding lawn mower carburetor:

  • Step 1. Preparation.
  • Step 2. Remove the outer covering of the engine.
  • Step 3. Inspection of Air Filters and their housing.
  • Step 4. Open the carburetor and disengage it from the fuel line.
  • Step 5. Unbolt the Bowl and clean the nuts.
  • Step 6. Switch the central gasket, change the needle, and check all connections.
  • Step 7. Use a Cleanser to clean the carburetor.
  • Step 8. Reassemble the parts of the carburetor and reattach.

This might be a lot to take in, but do not worry. We have got you covered up as we promised. Therefore, here are some home scale troubleshooting points that you can easily follow.

Common troubleshooting steps:

If you are unsure how to troubleshoot the problem, we have broken down the steps in simple and user-friendly instructions.

● Step 1. Preparation:

When you start, make sure the engine of the mower has cooled down. Safety measures should be your primary concern whenever you are doing repair work of any kind. Due to rusty or old fuel, the residue in the fuel tank can be highly toxic.

The essential thing is to make sure that you are working in a well-aerated area when disengaging a carburetor. If you are working in a garage or a workshop, open the door or any windows. It is suggested to use a ventilation fan to maintain the proper air circulation in such areas. Suppose your garage or workshop does not have windows for ventilation fans or doors that can sustain ventilation, you should consider working somewhere else to escape from personal harm or any property damage.

● Step 2. Remove the outer covering of the engine:

  1. Suppose you are the first time cleaning the carburetor. In that case, there is a crucial point to remember: record a video during the whole process or take photos of the assembly after each step to make reassembling much easier.

● Step 3. Inspection of air filters and their housing:

Principally, take out the screw holding on the air filter, then all screws holding on the carburetor, and finally pull the housing off. By doing this, the carburetor will become visible. Now separate the breather tube. The principal thing is to clean the carburetor to ensure that the air filter does not have any twigs, dirty grass, and debris. The obstructed or blocked air filter will generate black smoke that can be seen coming out of the muffler. It will obstruct our carburetor’s air passage, and thus it cannot “breathe” due to interruption.

● Step 4. Open The Carburetor and disengage it from the Fuel Line:

  • Slide off the carburetor from the mounting bolts, carefully disengage the fuel lines, and take out the component from the core assemblage. Please stay vigilant when removing the fuel lines as fuel dribbling might occur. It is better to have some piece of dusters or rags so that you should be prepared to catch the fluid because some fuel would certainly seep out of both the carburetor and the fuel lines. Fuel seepage ensures that your fuel line is perfect and hence no fuel obstruction is there. If there is no spilling, it may be possible you have blocked fuel lines, and you need to check that.

Step 5. The Bowl is unbolted, and nuts are cleaned:

At first, use a Cleanser or spray to clean around the carburetor bowl. A single screw grasps the Bowl; unthread that screw to set free the carburetor bowl. This nut is a jet with a hole, and you need to ensure that the hole does not have any barriers. This process is done by poking a paper clip or piece of wire inside it. Debris that remains inside the jet is one of the most common causes for a carburetor to stop working correctly, and thoroughly cleaning the hole could solve your problem. In the end, you should spray some of the carburetor cleaners on the nut. Also, if the Bowl is damaged or, for the most part, dirty, you should substitute it rather than trying to clean it.

● Step 6. Switch the central gasket, change the needle, and check all connections:

Now, you have to unthread the screws to release the prime bulb and base, take out a metering plate, diaphragm, and the central gasket between the carburetor itself and the Bowl, so there is the entire disassembled carburetor. If the gasket is rusty or old, clean it by scratching it off with sandpaper because this rusted gasket may affect the Bowl’s proper functioning. The damaged gasket should be replaced with the new one.

Once you have removed the Bowl, the float is linked to the carburetor through a pin. Remove the float pin to set the float and the needle-free. Inside the carburetor, there is a small gasket where the needle is placed; you should also change this, taking care of the fact that the new one should be fitted correctly.

After all the steps mentioned above, if the problem continues, we should check all the possible connections between choke plates and the carburetor’s throttle, as these things can get disordered when they become filthy and can stab and stick to one other. Likewise, continuous vibration and scratch can disengage screws with every passing moment, contributing to abnormal usage and supplementary carburetor issues.

● Step 7. Use Cleaner to clean the carburetor:

As all the small parts of twigs, grass, and other debris can get stuck into the carburetor, there is a need to use a  cleanser to clean all the sediments which are in the carburetor. These sediments can cause congestion of the air and fuel passage and decrease working effectiveness, thus halting the engine completely.

Luckily, you do not have to take the carburetor out of this engine to perform this action. We can use any of the lawnmower carburetor cleaners on the market, or something like WD-40. Use the Cleaner to clean the carburetor intake and outlet ports and the outside of the carburetor. Ensure that all the holes are free of dust and debris.

After you have cleaned the carburetor’s apparent surfaces using this Cleaner, you must have to check for any maintenance issues, such as old fuel, dirty air filters, old and rotten spark plugs, and deteriorated engine oil.

● Step 8. Reassemble the parts of the carburetor and reattach:

Following steps are performed to reinstall the carburetor:

  • Step 1. Dry and reassemble the Carburetor: Firstly, let the carburetor dry and then get back the Carburetor parts together, ensuring that you correctly positioned the diaphragms, gaskets, metering plate, and primer base as these are required along with the float needle and float.
  • Step 2. Organize the Bowl: The bowl gasket should be appropriately arranged, and reposition the Bowl is done if necessary.
  • Step 3. Reunite the Carburetor: Smoothly move the reassembled carburetor back on the mounting bolts and attach the throttle coupling to the throttle lever.
  • Step 4. Attach the fuel line: Attach the fuel line to the carburetor again.
  • Step 5. Reassemble the air filters: Relocate the air filter covering with the air filter and filter cover.
  • Step 6. Reinstall the exterior covering: Reinstall the engine cover.

After thoroughly inspecting the lawn mover, now when everything is reassembled, add fuel to its tank and start the carburetor. If the carburetor is perfectly cleaned, it will now certainly start up quickly.

Additional safety precautions:

In addition to clean a carburetor, be attentive that a filthy air filter can also cause a lawnmower engine to run rough. As for your annual lawn mower maintenance, you should replace the air filter and fuel filter at all times.

  • Usage of Fresh Fuel: you should use new fuel to avoid problems regarding delaying.  
  • Addition of Fuel stabilizers: Use fuel stabilizers to prevent the formation of residual fuel in the compartment of the carburetor, as it consists of additives that increase the residual fuel life.
  • Repair kit for Carburetor: Cleaners are readily available, which act as anti-rust agents and clean the grease. It helps you overhaul and substitute the faulty parts like the float or float needle, gaskets, and diaphragms. If the carburetor is still performing poorly, you need to change the old carburetor.  

Frequently Asked Question:

1. How will I get to know that my lawn mower carburetor is terrible?

These are four signs that your carburetor needs maintenance.

  • It just will not start. If your engine cranks and does not start, this is because of a dirty Carburetor.
  • Your engine “runs lean,” which means that the equilibrium between fuel and air is lost.
  • The engine is running rich.
  • It is flooded.

2. What are the ways to clean a Carburetor of a Lawn Mower without taking it out?

  • Step 1: Inspect where the problem is.
  • Step 2: Make the Inner Part of the Carburetor visible.
  • Step 3: Use Aerosol Cleaner to clean it.
  • Step 4: Remove the residual deposits.
  • Step 5: Replace the Carburetor Cover and Linkage.

3. Where should you spray Cleaner on a riding lawnmower?

Spray the carb cleaner on the choke shaft at the base of the carburetor’s throat to eradicate any additional dust after shutting the engine off. Replace carburetor cover and its linkage, place the air filter back in its place and screw the air filter covers back in its place.

Final remarks:

In a nutshell, we can predict that the engine shutdown, rough running, and stalling problems are primarily linked to the defective carburetor. Major issues regarding carburetor are caused due to various obstructions from dust, paint, and gasoline sediments. The dirty particles can clog the carburetors and filters’ holes and jets, eventually, cause these problems. The main fuel jet is easily clogged, but fortunately, it can be fixed quickly, as we have discussed above. Regular carburetor maintenance will ensure that these clogging issues are minimized and are essential steps to prevent future problems. In addition to that, the fuel quality must be adequately regulated by making sure that fresh fuel is utilized and fuel stabilizers. Better maintenance of the machine always guarantees a longer service life.