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How to clean a carburetor on a lawnmower without removing it

With the weather cleared, you are all set for a mowing session in your garden. You try to kick start the engine of your tried and tested lawnmower that doesn’t seem to start. Your experience with engines tells you that there is a good chance that the fault lies in the carburetor that can be clogged and needs to be cleaned. Luckily this is something you can do yourself, and who would want to take the trouble of taking his entire machine to a mechanic just for a minor carb cleaning. If you’re looking for an easy solution, then you have come to the right place.

Most often, lawnmower carburetors require cleaning due to the dirt build-up in them, which causes your engine to misbehave. If you’re a DIY mechanic, it’s not a good idea to fully open the entire machine to expose the carburetor. There are ways to solve the problem without removing the carburetor.

How to clean a carburetor on a lawnmower without removing it:

  • Step 1: Access the situation to check why does the carburetor need cleaning
  • Step 2: If it needs to be cleaned, remove the air filter so that the carburetor becomes visible
  • Step 3: Unscrew the carburetor jets and clean them using a carb cleaner or a compressed air gun
  • Step 4: When finished, reassemble the parts and start your engine by adding fresh fuel

If you haven’t performed these cleaning steps before or aren’t sure which components to remove, don’t panic. We have broken down the entire information for you to digest in this article. Stay tuned.

Steps to Clean Lawnmower Carburetor:

Suppose you’re looking to service the carburetor without removing it. In that case, you should follow the steps below that guide you thoroughly.

● 1. Analyze the situation before cleaning:

You should know the reason why you are looking to clean your lawnmower’s carburetor in the first place. The primary function is to supply a correct mixture of air and gasoline to the engine for combustion. The engine produces power. Over time, dust settlements begin to develop within carburetor jets that can eventually clog these jets. Despite air filter, it is highly likely that your carburetor witnesses clogging issues after a specific time, and that is indicated with your engine problems.

– Step 1: Do an initial checkup:

If your engine isn’t starting correctly, or if it just stalls after starting, or if it’s not producing enough power. Then it means there are debris deposits in the carburetor of your engine. Thus, it is high time to service your carburetor. If you’re not a proper mechanic, we recommend avoiding disassembling the entire carburetor and cleaning it without completely removing it. For this purpose, we have summarized the process in easy steps for you.

– Step 2: Record your steps:

Now that you are looking to disassemble the parts, it is better to start by taking the mower’s initial pictures. These pictures give you a better idea of where to put the parts during their assembly if you forget about which thing goes where.

● 2. Expose the carburetor by removing the outer components:

This step is where the disassembly begins. You can refer to the full instructions below:

– Step 1: Remove the air filter:

The air filter is situated at the exterior of the mower adjacent to the fuel tank. It comes off usually in most mowers. For that, you might need a screwdriver to remove the screws securing the filter. Now that it has come off, it might be a good idea to clean it using soap water. A dirty air filter might be one of the reasons that led to the carburetor’s clogging in the first place.

– Step 2: Remove the fuel lines:

Now that your carburetor is visible after removing the air filter, you should detach the fuel lines leading to it using nose pliers. Keep a plastic bottle in which you can insert the fuel line, so that whole of the fuel drains into it. Note that the entire fuel in your tank needs to be disposed of properly. Since it is probably the primary source from where the dirt came from in the first place. A yellowish fuel means that it has become stale.

– Step 3: Unscrew the jets:

Afterward, use a wrench to unscrew the bolt underneath your carburetor bowl (which also has a jet). You should remove the bowl as the nut securing it has come off. Then slowly remove your gaskets and check if they are in condition or not. Assess your float by pressing it. If it gives a clicking sound, it means that the needle is going precisely into its original position, and that is how it needs to be. Place the jets and the bowl separately so that they can be cleaned.

● 3. Clean the components:

The parts that have been removed are cleaned in this step.

– Step 1: Cleaning the jets:

The nut that secures the bowl is also the main jet with a tiny hole for air passage. This jet is one of the most common sites for debris build-up. There are many ways of cleaning it. You can use a thin metal wire and pass it through the jet to remove any dirt. Or you can use an Aerosol cleaner for carburetor cleaning and spray some of it onto the jet. Also, if you see some flakes on the nut’s side, it is always better to remove them using sandpaper.

– Step 2: Cleaning the bowl:

Before cleaning the bowl, first access whether it can be reused or not. If scales or rusts have developed inside to a great degree, then it’s a good idea to buy a new one and replace it altogether. In case you want to clean it, you can put some carburetor cleaner and scrub it afterward with sandpaper.

– Step 3: Spray the interior with the cleaner:

It would help if you now used the aerosol spray to effectively clean the carburetor’s interior connected to the lawnmower body. It might also be useful to use a compressed air gun for spraying that eventually removes all the dust developed over time. It is recommended that you pour the carburetor cleaner at the carburetor’s center with the engine running. Due to the running engine, liquid flows entirely through the jets leaving behind no clogging. However, it would help if you never touched the carburetor when the engine’s on.

● 4. Reassembly of the parts:

Now that your cleaning is complete, it is high time to refer to the pictures you earlier took and figure out which part fits where. First, you should assemble the carburetor parts by securing the jets and renewing the gaskets where needed. Screw the bowl nut tightly and use a dry rag to clean it from the outside gently. Connect the fuel lines back to the carburetor and secure them in place by tightening their claps. Now, put the air filter and the fuel tank back into their original positions and screw them tightly. Your carburetor cleaning is now complete. You can add fresh fuel and start the engine to check if your initial problems are solved.

Related Questions:

● 1. Can you clean a lawnmower carburetor without removing it?

You can clean a carburetor without disassembling it completely. During this cleaning, only the bowl nut and the bowl come off that are cleaned separately. The rest of the unit that hasn’t been disassembled should be cleaned with an aerosol cleaner.

For carburetor cleaning, you should first determine the age of your component to decide if cleaning solves the problem or not. If your carburetor is old enough and has been serviced quite frequently in the past, then we recommend that you should replace it with a new unit. If it’s not that old, you can always clean it to remove the dirt or debris built-up over time.

● 2. Where do you spray carburetor cleaner on a lawnmower?

It is highly preferred that you spray the carb cleaner when the engine is running. To clean, you should place the cleaner’s tip at the center of the carburetor at the base of its throat and spray the liquid. Doing this on the running engine allows the cleaner to flow thoroughly into the jets and the holes, thereby cleaning any sludge deposits.

● 3. What can I use instead of carburetor cleaner?

If a carburetor cleaner is unavailable, a brake cleaner is a reasonably good substitute. It is pretty compatible with use on carburetors and can dissolve grease and sludge build-ups. It is made up of chemicals that evaporate after drying, thus leaving behind no residue.

● 4. How do you know if your carburetor needs cleaning?

If you face either one of these four below cases with your engine, then it is a sign showing your carburetor needs servicing:

– The engine does not start at all

If the engine does not start at all, it is a sign that the carburetor is so dirty that the air-fuel charge cannot reach the engine.

– The engine is running lean

Engine running lean is when the air-fuel mixture is disturbed (increased mainly). Typically, the air ratio to fuel ranges from 12:1 to 15:1. If too much air is fed to the engine or insufficient fuel is provided, it produces a popping sound at the air inlet. This condition happens when the fuel jets are clogged.

– The engine is running rich

Engine running rich is the opposite of the above case. In this case, excessive fuel is being supplied to the engine. This situation causes black smoke to rise from the exhaust.

– The engine is flooding

Engine flooding occurs when the needle valve in the bowl is clogged, due to which it does not, and the fuel floods the carburetor. This condition eventually disturbs the air-fuel ratio, thus indicating the need for carburetor cleaning.

Final Remarks:

Lawnmowers need maintenance as frequently as any other machine. Now since they are subjected more to dirt and debris, it is quite possible that clogging can result in various types of problems. While dealing with cleaning, you must specifically ensure that no fuel leakage occurs or the fuel has been disposed of entirely. Be very careful while using the carb cleaners as they can be hazardous to inhale. It is better to perform the cleaning operation outdoors in sunlight. As a preventative measure, we always recommend using a fuel stabilizer and often changing your fuel after regular intervals. This timely maintenance prevents it from getting stale, thus avoiding frequent carburetor cleaning.