In Brief: How to Clean a Carburetor on a Riding Lawn Mower
There are two ways to clean a riding mower carburetor. The first method is to spray it with carb cleaner, which will remove simple build-up. This is a good method for routine maintenance. A more complex method of cleaning is disassembling the carburetor and soaking it in solvent. Only disassemble your mower if you have mechanical experience.
Carburetors are an essential part of many petrol engines. The purpose of the carburetor is to regulate the flow of fuel and air into the cylinders.
Although engines in vehicles have largely switched to fuel injection systems, carburetors are still commonly used on small engines, including those found in gas lawn mowers and weed eaters.
If you drive a riding lawn mower, you need to be aware of issues that can happen with the carburetor. As part of regular maintenance, learning how to clean the carburetor on a riding lawn mower can help you get better performance out of it and extend its useful life.
2 Methods for Cleaning a Riding Lawn Mower Carburetor
Generally speaking, you can clean a carburetor two different ways. You can either use a carburetor cleaning spray (carb cleaner) or remove the carburetor and clean it by hand.
Method 1: Using Carb Cleaner
For regular maintenance, carb cleaner spray usually does a great job at improving the efficiency of your mower’s carburetor. It’s a simple way to clear away any build-up of sludge or small debris, but it won’t be as good for large build-ups or very dirty carburetors.
Carb cleaner can be applied in a few simple steps:
- Step 1: Remove air filter and carburetor hood
Remove or open the mower’s hood.
Find the air filter cover and remove it. You may need to use a screwdriver to remove the cover. Once the cover is off, take out the air filter and set it aside.
Take out the external cover from the carburetor body. This should have been exposed when the air filter was removed.
- Step 2: Spraying carb cleaner in the engine
Turn on the lawn mower. The engine needs to be running before you start spraying carb cleaner.
If you have already been using the mower, wait to turn it on again until the carburetor has dried out and cooled down.
While the engine is running, spray carb cleaner directly into the opening of the carburetor. Do this for a few seconds to allow the cleaner to penetrate the interior parts of the carburetor.
- Step 3: Turn off and Re-assemble
Turn the engine off, then spray carb cleaner on the choke valve, which should be located at the base of the carburetor.
Replace the parts where they belong, starting with carburetor cover, then the air filter, and finishing with the air filter cover. Close the mower’s engine cover and store it as usual.
See an example of carb cleaner spray in action:
Method 2: Cleaning by Hand
When a deeper cleaning is necessary, or if you’re servicing your riding mower’s carburetor because of engine failure, hand cleaning is often a better choice.
You can be more thorough and give your carburetor the best chances of success by removing everything that could be preventing it from working properly.
This is the more involved method, requiring more time, patience, and tools. It’s not something you should try unless you have some basic understanding of engines or basic experience with mechanical devices. If you do decide to clean your carburetor by hand, follow these steps carefully:
Step 1: Open the mower and get to the carburetor
Open up the mower’s hood. Most carburetors are located underneath the air filter in the mower engine bay.
First, remove anything external covers to gain access to the air filter. Unscrew it or turn the securing knobs to release it. Remove the air filter and set it aside.
Once the air filter is out, unscrew and remove the air filter housing and the blower housing underneath it. The carburetor should be in clear view at this point.
Step 2: Removing the carburetor
Start by locating the fuel intake line. This is usually a black rubber hose leading into the side of the carburetor. Clamp the fuel line to prevent excessive spilling when you remove it. You should expect some fuel to spill, so be prepared with a rag to clean it up.
The fuel line is likely secured to the carburetor with a clamp. Loosen the clamp and disconnect the line, cleaning up drips as you go.
Next, you want detach the carburetor from all other connected pieces. Before you do this, take a picture of the connections to make sure you can get it back in place when you’re done.
The main connections you’ll be working on are the air intake mount with its connected breather tube, the fuel solenoid, and the mounting studs.
Once you’ve undone the connections, remove the throttle rod, throttle spring, and choke rod from the carburetor itself. You should now be able to pull the carburetor free from the engine easily.
See how to remove a carburetor here:
Step 3: Cleaning the carburetor
At this stage, you have two different options.
Option 1: Place the whole carburetor in a bowl. Pour a metal-safe, anti-corrosive solvent to cover it. Let it soak for 2-3 hours or less to clean the parts.
Do not do this if the carburetor has rubber parts. Do not soak for longer than 3 hours.
Option 2: Disassemble the carburetor completely. Wash, rinse, and dry each part individually before reassembling them.
Do this carefully to avoiding losing, breaking, or misplacing pieces. Don’t do this method unless you have some experience working with technical machinery.
Step 4: Re-assembling the engine
Replace the parts in the opposite order to how you removed them, being careful to secure each connection tightly. Reference the pictures you took during disassembly to confirm you’re doing it correctly.
There shouldn’t be any loose screws, hoses, clamps, or other connection points. Turn on the engine to test it.
Why Do Carburetors Need to Be Cleaned?
If the carburetor is clogged or dirty, it can impact the performance of the engine. In a riding lawnmower, this might look like the engine dying shortly after you start it, or the mower surging and jumping.
Heat can sometimes make carburetor problems more obvious, so you might also notice it having problems after a few minutes of use when they engine is warming up.
Over time as you’re using your mower, the carburetor can collect dirt, lawn debris, and grime. If you use your mower regularly, you should do a simple cleaning a few times every year.
If the mower sits for long periods of time without use, especially if there’s fuel left in the tank, clean it before you start using it again.
A dirty carburetor can upset the balance of fuel and air. If this balance is thrown off, that can cause the engine to choke up or cut out. There has to be a steady mix going to the cylinders to keep it running smoothly.
If you’re running into engine trouble, especially the engine cutting out, it may be time to service the carburetor.
Although it might be new territory for you, cleaning your riding mower’s carburetor is a valuable skill to learn. You’ll keep your mower running better, improving its efficiency and extending its useful life.
Regular use of carb cleaner spray is both simple and effective, but a deep cleaning might be necessary if carb spray doesn’t fix the problem.
Do you have any questions about how to clean a carburetor on a riding lawn mower? Comment below!