How to Clean a Lawn Mower Carburetor Without Removing It (Yes, It’s Possible)

Removing the carburetor 20-thread bolt using an M10 wrench sounds more like an engineering project than a quick lawn mower repair for a Saturday morning. Carburetors are fairly complex mower parts that annoyingly need attention if you want to keep your lawn mower running smoothly. So, do you have to know a lot about engines and have a tool collection to clean a carburetor? And do you have to remove the carburetor to clean it? Let’s take a look.

Can You Clean a Lawn Mower Carb Without Removing It? (The Short Explanation)

If you’re suffering symptoms of a bad carburetor, you’ve probably come across a lot of people who recommend removing the carburetor to clean it. Even though I say this myself, it’s not the only solution. A carburetor doesn’t need to be stripped down and squeaky clean to work well. So, do you need to remove the carburetor to clean it? No.

There are two methods to cleaning a carburetor while it stays on the lawn mower. The first is a chemical spray clean, and the second is a jet removal clean. So let’s go over how to clean a carburetor without removing it.

Chemical Spray Cleaning

• Remove the Air Filter Cover
• Remove the Air Filter
• Spray the Outside of the Carburetor with Carburetor Cleaner
• Brush the Outside of the Carburetor with Small Nylon Brush to Remove Dirt & Grime
• Start the Engine
• Set Engine to Fast Idle
• Spray Cleaner into Carburetor
• Run the Engine for Several Minutes to Burn Off Cleaner
• Replace Air Filter
• Replace Air Filter Cover
• Switch Off the Lawn Mower

Jet Removal Cleaning

• Switch Off the Fuel
• Remove the Fuel Cup Bolt
• Remove the Fuel Cup
• Remove the Jet Retaining Screw
• Remove the Jet
• Clean the Jet
• Replace the Jet
• Replace the Retaining Screw
• Replace the Fuel Cup
• Replace the Fuel Cup Bolt
• Switch On the Fuel

How to Clean a Lawn Mower Carburetor Without Removing It? (Step By Step)

Now that you have seen how to clean a lawn mower carburetor without removing it let’s take a more detailed look at the steps you’ll need to follow.

Step By Step Carburetor Chemical Spray Cleaning

The first step is to remove the cover from the air filter to gain access to the inside of the carburetor. You may find that your cover is secured with a screw, so you’ll need to grab a screwdriver to remove the fastener.

Next, remove the air filter from within the filter housing and set it to one side. If your lawn mower has two filters, you’ll need to remove both of them, including the air filter and pre-filter.

Now, grab your carburetor cleaner and give the outside of the carburetor a good spray. Try to get the cleaner into all the nooks and crannies so that it really gets to work on all the dirt.

Next, use a small nylon brush and start working off all the dirt and grime. I like to use an old toothbrush for this part of the cleaning. Also, don’t be tempted to use any type of metal brush as the carburetor is made of a soft alloy that is pretty delicate. A toothbrush should work just fine.

Once you are happy with the outside of the carb, you can go ahead and start the lawn mower’s engine and set the throttle to a fast idle.

With the engine running, use the same cleaner and give the inside of the carburetor a good spray. A couple of seconds should be enough. Just make sure that you don’t stall the engine. Once the engine has burned off all the cleaner, give the carburetor another spray inside. I like to repeat this a couple of times to make sure it’s getting a good thorough clean.

Next, allow the lawn mower to run for a few minutes after you believe the engine has burned off all the cleaner. This allows any of the cleaner sticking around to burn off completely.

The last job is to reinstall the air filter and replace the air filter cover. If you had to remove a screw for the cover, remember to screw it back in. Also, this is the perfect time to inspect the air filter and make sure it’s not soaking in oil or worn out. You could even clean the air filter before putting them back in.

Finally, switch off the lawn mower or head out and tackle your lawn.

Tools & Parts to Spray Clean Your Carburetor

• Spray Carburetor Cleaner
• Screwdriver

Step By Step Carburetor Jet Cleaning

The first job is to switch off the lawn mower’s fuel if you have a cut-off valve. This will save any unnecessary fuel spillage.

So, start by removing the bolt on the bottom of the carburetor located at the center of the fuel cup. You’ll need a small wrench for this. Now, for some of you guys, this bolt is the actual jet. This means you can skip the next steps until we get to the cleaning part. For you guys that don’t have this type of carburetor, keep following along.

Next, once you have removed the bolt, you should be able to pull the fuel cup off the carburetor. Just be a bit careful, as the cup will probably be full of gasoline.

Now, located where the fuel cup bolt would connect to the inside of the carburetor, you’ll find a screw. Take a screwdriver and remove this retaining screw. Once you take this screw out, the jet should fall out. Some lawn mowers incorporate the jet into the screw, so just take a close look.

Next, it’s cleaning time. So, if you take a look at the jet, you should see a clear hole all the way through it. I find holding it up to the light helps. What you are going to need to do is remove any dirt that is clogging the hole. I find that a thin wire works well enough. Once you have it cleaned out, you can give it a spray of your carb cleaner and wipe off any grime.

Finally, it’s time to put the few bits back on the mower. So the order is the jet, screw, fuel cup, and finally, the bolt. For you guys with just the bolt/jet, pop it back into the mower and tighten it up with your small wrench.

That’s all there is to it. It’s pretty straightforward and takes no time at all. Just don’t forget to turn the fuel back on.

Tools & Parts for Carburetor Jet Cleaning

• Small Wrench
• Screwdriver
• Small Wire
• Spray Carburetor Cleaner

Cleaning a Mower’s Carb: To Remove or To Not Remove

So, we have discussed how to clean a lawn mower carburetor without removing it, but will this solve all your carburetor issues? Well, it depends. You’re going to find that spraying the cleaner directly into the carburetor is going to cure problems from fuel impurities, fuel gum, and bad fuel in your mower. However, a clog in the carburetor jet needs a bit more work, like my jet cleaning method. Also, you’re going to find that some lawn mowers don’t offer enough room to remove the carburetor jet. This means the carb is going to have to come off.

So, if you have a lawn mower like a Yard Machine with a Briggs & Statton engine, you’ll probably have to remove the carb, but give the chemical spray a try first.