How to clean a Honda lawnmower carburetor, step by step


When you notice that your Honda lawnmower lacks power and is difficult to keep running, you know that there is a problem with the engine. As is the case, if your trusty honda mower doesn’t start at all, there can be several things to blame. High on the list of causes is a dirty carburetor. A properly working carburetor is a critical part of the lawnmower engine, as it turns gas into vapor and feeds it to the engine.

If the carburetor is not functioning correctly, your Honda lawnmower will not be able to start or runs poorly. Maintaining your carburetor is needed for long-term usage and reliability. This blog will explain how to clean the carburetor in your Honda lawnmower.

How to clean a Honda lawnmower carburetor, step by step:

  • Step 1: Remove the outer casing of the engine area.
  • Step 2: Check air filters and their case.
  • Step 3: Unscrew the carburetor and detach the fuel lines.
  • Step 4: Unhook the float bowl and clean the nuts attached.
  • Step 5: Clean the main gasket and the needle.
  • Step 6: Inspect all connections, including screws and washers.
  • Step 7: Clean the carburetor’s jets by using Carburetor Cleaner.
  • Step 8: Reassemble and reattach.
How to clean a Honda lawnmower carburetor, step by step 1
(CC BY 2.0) by sridgway

Steps to clean a Honda lawnmower:

It is easy to clean, tune-up, or repair your Honda carburetor. It involves some simple steps. If you add cleaning the carburetor to your maintenance routine, you can enjoy long-term use of your mower and protect it against failures.

● Step 1. Remove the outer casing from the engine area:

The first step is to loosen the fuel tap. If your mower is gas-powered instead, remove the gas from the gas valve. Then remove the casing from the engine part. It can be done by simply opening some nuts here and there. This should reveal the Lawn mower’s insides, and the different parts should be visible now.

After you have removed the cover, it is a good idea to disconnect the spark plug cables. This way, you ensure that the engine can not unintendedly start. Also, try to park the Honda lawnmower on a hard surface that can deal with some gas spill.

Tip: If you are cleaning the carburetor for the first time, there is a helpful tip. Make a video during this process or take some photos of the assembly after each step. This will make the reassemble much easier later on.

● Step 2. Check air filters and their case:

After removing the engine cover, you should see the air filter and the carburetor. Disconnect 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 Honda gas lawnmowers have a breather tube.

An essential part of cleaning the carburetor is to verify that the air filter is clean of twigs, muddy grass, and dust. A bunged or blocked air filter will form black smoke, which can be seen from the muffler. It will stop the air from getting into the carburetor, so it cannot “breathe.”

● Step 3. Unscrew the carburetor and detach the fuel line:

Remove the carburetor by unscrewing the mounting bolts. Carefully disconnect the fuel lines, and take out the main assembly. Please stay cautious while you are disconnecting the fuel lines as fuel leaking will occur. It is a good idea to have some rags prepared to wipe the fuel coming from both carburetors and the fuel line. Fuel spilling is a good sign, as it ensures that your fuel line is in good condition and that there is no obstruction there. If no spilling occurs, it means the fuel lines may have been clogged and need maintenance.

● Step 4. Unhook the float bowl and clean the nuts attached:

The float bowl is a small bulgy part present on the carburetor. It can collect a large amount of residue or slime on it. This residue will decrease the Honda’s carburetor functioning capacity and can cause problems when you start or use it. Initially, clean the carburetor bowl using the carburetor cleaner or spray. A single screw holds the bowl; remove that screw to release the carburetor bowl. This nut is a jet with a hole, and you need to make sure that this hole is clean. This is easy to do by poking a paper clip or a piece of thin wire inside it. Debris present inside the jet is one of the frequent reasons why a carburetor stops working, and just cleaning the hole will fix this problem. At last, spray some carburetor cleaner on the nut. If the bowl is impaired or predominantly dirty and is difficult to clean, you should consider to replace it rather than clean it.

● Step 5. Clean the main gasket and the needle:

You need to unthread the screws to remove the prime bulb and base. Remove the metering plate, the diaphragm, the main gasket within the carburetor itself, and the bowl. When you have done this, the carburetor is disassembled. If the gasket is old and rusty, tidy it by rubbing it carefully off with sandpaper. The rust might disturb the bowl’s functionality. If the gasket is entirely damaged, extract the old one and replace it with a new one. Check the manual from your Honda lawnmower if it contains more details on the exact version you need.

Once you have removed the bowl, you will notice the float is fastened to the carburetor with a pin. Removing the float pin will release the float and needle. Inside you will see a small gasket that you should replace if it does not look ok. Take care that you fit the new one the right way around (take pictures or a video).

● Step 6. Inspect all connections, especially screws and washers:

If the problem persists after the previous cleaning steps, you need to check all the possible connections between the choke plates and the carburetor’s throttle of your Honda Lawnmower. They can become dirty and can bind and stick to each other. Inspect the float chamber, float pin, and float valve tip for any damage or dirt. It is good to check the mower’s carburetor washers and screws if there are any wear and tear. Vibration, abrasion, and prolonged use of the carburetor can slowly loosen the screws causing vibrations.

● Step 7. Clean the carburetor’s jets by using the carburetor cleaner:

The Honda mower’s carburetor takes in fuel through small jets. These jets vaporize the gas that is then combusted with a spark from the spark plugs. If the cleaning in step 4 did not help enough, the jets need to be cleaned more thoroughly. Small debris like grass particles, dust get into the jets, and they may get blocked. These deposits can clog the air and fuel passage and decrease efficiency. Another cause can be when the gas is not of good quality (high octane) or merely is not clean. When you are done cleaning the carburetor’s transparent surfaces with the cleaner, you must examine any other maintenance problems, similar to old fuel, filthy air filters, old and fouled spark plugs, deteriorated engine oil, and more.

● Step 8. Reassemble and reattach:

After inspecting and cleaning your Honda lawnmower carburetor thoroughly, you can reassemble it and put it back in its original location. If you made some photos or video, you could check how it needs to be fitted back. When everything is back in place, add fuel to the tank and start it up. It should start up easily and quickly.

Safety Precautions:

Safety should always be your primary concern whenever carrying out repair work of any kind. Take care of the following points:

  1. Cooled engine: Before you start, make sure the mower engine has cooled.
  2. Work in an area with some ventilation: Certify that you are working in a properventilation area when taking apart the carburetor. If you are functioning in a garage, unlock the door and windows. It is urged to use an aeration fan in such areas. If your garage or workshop does not have windows or doors you can open, you should consider working somewhere to avoid personal injury or property damage.
  3. Always use fresh fuel: Usage of new power avoid major problems regarding stalling. Old or rusty fuel in the fuel tank can be highly noxious. Do not keep the energy for an extended period in the carb’s cabin.
  4. Use fuel stabilizers: Usage of fuel stabilizers avoids the residual formation in the compartment, as it consists of chemical additives that enhance the residual fuel life.
  5. Carburetor repair kit: Carburetor Cleaners are readily available in the market, behave as anti-rust agents and sifting the grease. It will help you in servicing and replacing the defective components like the float and float needle, gaskets, and diaphragms.

Frequently Asked Questions:

1. What is the most simple way to clean a carburetor without taking it apart?

You need not remove the carburetor to clean it. If you have lesser time or do not want to face the technicalities, you may only remove the carburetor bowl, which is often the main culprit. Spray the cleaner inside, wait for some time and then spray again to ensure the coverage.

2. Can you spray carb cleaner in the spark plug hole?

Yes, you can directly spray the carburetor cleaner into the carburetor opening. Then, disengage the spark plug and spray a 2-second explosion down the spark plug hole. Whether it is a two-stroke or four-stroke engine, it will not damage it. Some people believe that it must not be used on a 2-stroke engine, but if it is used only for priming, it will not hurt a thing.

3. Why does my Honda mower surge?

The gas tank lid has a minor hole, which permits air to run into the tank and build backpressure to fuel the carburetor. Dust or dirt can be clogged up this hole. Consequently, the carburetor will not get sufficient fuel, leading to surging. Surging can also occur because of water fouling your fuel.

Final remarks:

The carburetor is an essential part of your Honda lawnmower and performs a complex function. Carburetors need regular maintenance. It is easy to take the carburetor apart and clean it using our step by step approach. The blog explains how to find and disassemble the carburetor. Now, you can easily clean the parts with these simple to follow steps. Give it proper care, time, and notice for any cracks, loose seals, and broken parts. If the carburetor still executes poorly, you may need to replace the old carburetor with a new one.  

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