Lawn mower muffler cleaning. How to Clean a Lawn Mower Carburetor for Annual Maintenance

Knowing how to locate and clean the carburetor on your lawn mower can keep it running smoothly for years to come.

By Timothy Dale | Updated Jun 3, 2022 11:19 AM

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A common problem encountered by many homeowners is finding that their lawn mower engine won’t start when they try to mow after a long winter season. This can be a sign that your mower’s carburetor is gummed up or even corroded, so it’s important to perform annual maintenance at the beginning of the mowing season to address any problems that could have been created over a long period of disuse.

Other signs of a dirty or restricted carburetor include the engine starting but stalling during use, the muffler emitting black smoke, a significant increase in fuel consumption, or the engine running rough during regular use. Keep reading to find out how to clean a lawn mower carburetor, as well as how to diagnose if you need lawn mower carburetor cleaner or more involved carburetor repair.

• Screwdriver
• Needle-nose pliers
• Nut driver
• Socket set
• Gloves
• Carburetor cleaner
• See full list «
• Bucket
• Compressed air

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BEFORE YOU BEGIN

In the event a dirty carburetor isn’t the reason your lawn mower won’t start, it’s important to first make sure something else isn’t causing the issue. Double-check that there’s fuel in the tank, the fuel valve is on, and the spark plug is in decent condition before spraying aerosol lubricant or carburetor cleaner into the throat of the carburetor. After spraying the carb cleaner, attempt to start the engine. If the engine runs at all, then the issue is with the fuel system. If the engine refuses to start after several tries, however, then the problem may be more serious. In that case, take your mower to a small engine repair shop.

STEP 1: Clean the outside of the lawn mower engine.

The purpose of learning how to clean a carburetor on a lawn mower is to remove any dirt and debris that could be causing the engine to run rough, so begin the lawn mower carburetor cleaning process by cleaning the outside of the engine while it is turned off. This makes it easier to keep the internal parts of the carburetor clean during disassembly.

Also, it’s necessary to take the time to clean your work area, which should be well-lit to avoid losing any small parts while you work. Have a clear space on your workbench where you can disassemble, clean, repair, and reassemble the various parts of the carburetor.

STEP 2: Remove the air filter to access the carburetor.

In order to access the carburetor in your lawn mower, you need to remove the air filter housing. The air filter typically sits overtop of the carburetor. Inspect the air filter to determine if it’s attached with clips or screws, then use a screwdriver to loosen the fasteners and place them in a safe location for reinstallation. Next, remove the air filter. It’s a good idea to inspect the air filter and either clean or replace it if necessary. If you have difficulty removing the air filter, you should be able to find detailed information in your lawn mower’s manual to help with this part of the process.

STEP 3: Remove the carburetor.

Wearing durable gloves for skin protection, use a carburetor cleaner for lawn mowers to spray into the throat of the carburetor or clean the part’s exterior. To clean the internal pieces of the carburetor, though, you will need to remove it entirely from the engine. Use a nut driver or socket set to remove the two bolts that hold the carburetor to the engine, then disconnect the throttle and choke linkage cables from the carburetor.

Make sure to place any fasteners or small pieces in a safe location for reinstallation, and note (or photograph) the location of any cables or hoses so you can put them back in the proper place. Prepare a bucket or bowl to catch the fuel before removing the fuel lines from the nipples of the carburetor housing with needle-nose pliers. If no gas comes out of the fuel line, you may have a plugged fuel line or fuel filter, which will have to be addressed before reassembling the lawn mower.

Once the carburetor is disconnected, pull it off of the mounting studs, taking care to avoid damage to the main gasket between the carburetor and the engine. Also, make a note of the position of the carburetor so that you don’t reinstall it upside down. Place the carburetor in a bucket to allow any fuel to drain.

STEP 4: Disassemble the carburetor.

A key reminder before disassembling your carburetor is that every piece you remove needs to be put back in the same position. Prepare an appropriate place to disassemble the carburetor if you haven’t already, and consider taking pictures while you work to prevent confusion during reassembly.

With the carburetor in the middle of your clean work area and while wearing gloves, start the disassembly process by cleaning around the bowl with a carburetor cleaner. Next, unbolt the fuel bowl and ensure the hole in the nut is clear of any obstructions by poking a paper clip or piece of thin wire through it. Then, remove the float, which should be attached to the carburetor with a hinge pin, and also remove and replace the needle, if necessary. Keep all of the parts grouped together.

STEP 5: Replace any worn-out parts.

Even the best carburetor cleaner cannot repair worn-out parts. Should you spot significant wear and tear on any parts, including the float, pin, needle, or gaskets, then you should get a carburetor repair kit for your specific carburetor to make necessary repairs. Some carburetor parts, like gaskets, wear out more quickly than other parts. When planning your annual carburetor cleaning, it’s recommended to have spare parts ready on hand to avoid taking the carburetor apart more than once. Simultaneously replacing the mower air filter also helps to streamline the maintenance process.

STEP 6: Clean the carburetor and carburetor parts.

With the carburetor disassembled and your gloves on, you will be able to spray carburetor cleaner inside the carburetor housing and clean the various parts. Carb cleaners come in aerosol cans that are great for quick, efficient cleaning, but you can also purchase carburetor cleaner in a bottle or jug.

If you prefer to use a liquid carburetor cleaner over a spray cleaner, then you will need to pour the cleaner into an empty bucket where the parts can soak. Wire the larger parts of the carburetor together, then carefully lower them into a bucket filled with carb cleaner. Use a piece of aluminum screen or a fine-mesh basket to wrap the small pieces of the carburetor before placing them in the bucket, as well. Leave the parts to soak for about an hour before removing them from the cleaning solution.

STEP 7: Reassemble the carburetor.

Rinse the carburetor parts with water to remove excess carburetor cleaner. Then, blow dry the parts with compressed air or let them air dry. It’s essential that the parts are completely dry before reassembly.

When you’re confident that the carburetor parts are dry, you can begin putting the carburetor back together. Use any pictures you took during disassembly to ensure that you are correctly reassembling the parts.

Once the carburetor is reassembled, mount it on the lawn mower, reattach the throttle and choke linkage cables, and reinstall the fuel lines. Fasten the bolts on the carburetor and reattach the air filter to the mower.

STEP 8: Test the lawn mower.

After you have reassembled and reinstalled the carburetor and air filter, add fuel to the gas tank and start the lawn mower to ensure that the maintenance was a success. Ideally, cleaning the carburetor should allow the engine to start up easily, but if you continue to experience problems with starting your mower, take the lawn mower to a small engine repair shop for further diagnosis.

Final Thoughts

To get the longest life possible out of your mower, it’s necessary to perform regular maintenance throughout the year. This includes cleaning the carburetor at the beginning of the mowing season, winterizing your lawn mower at the end of the mowing season, and changing oil, replacing spark plugs, and sharpening blades as needed. If you neglect regular mower maintenance, it may break down in a relatively short period of time, costing you more in expensive repairs.

Lawn mower muffler cleaning

…Building Neat Things in a Small Space

Sunday, April 4, 2021

Repairing a Lawn Tractor Muffler. A Tale of Baling Wire and Bubble Gum

And so this weekend I hauled my old lawn tractor out from its winter hibernation. After giving the battery a quick charge and adding some fresh gas to the tank, I started the old girl up for the first time this year.

I’ve had this tractor for about 10 years and it always provided faithful service in keeping the grass around the house nice and trimmed.

So I was a bit bummed out when, after starting the engine I was greeted with a metallic clang and a really loud noise coming from the engine.

Hopping off the tractor, I immediately found the cause. On the ground, in front of the tractor, I found a large metal box. more commonly referred to as a muffler.

On the tractor itself, where the muffler used to be was now a length of straight pipe coming out of the exhaust manifold of the engine.

Now in certain circles, I know some people would consider having a straight pipe for an exhaust system as the summit of cool, but considering that this was a lawnmower that will be circling around my property for an hour or 2 each week, I don’t think my neighbors will think it very cool to run without a muffler.

Running to the computer I did a quick search for what a new replacement muffler would run me. I was a bit shocked. at what I found.

A new OEM muffler was going to cost me over 100 once I factored in the shipping costs. To add further insult to injury, the muffler was also on backorder so it would be a while before I got it if I did order it. The fact that it was on backorder also told me that this was a fairly common wear item for my tractor.

I was not very keen on shelling out 100 for what was basically a metal box. Secondly, I had visions of the muffler arriving in the fall, after a season of me slowly going deaf from cutting the grass.

Trying to figure out my options, I took a closer look at the muffler parts.

Structurally, the muffler looked to be in really good shape, there were no obvious rusted-out areas on it or the exhaust manifold pipe, and the metal still had almost all of its silver paint still on it.

Looking closer at where the pipe attached to the inlet of the muffler, I noticed that it appeared to have a pretty clean break at the opening.

Looking at the end of the pipe, I also noticed the remains of a welding joint, which provided more evidence that the pipe was welded to the muffler‘s intake.

In essence, the muffler fell off because the weld failed on the joint between the pipe and the muffler.

So the solution to this problem is to reweld the pipe back onto the muffler, a far cheaper, and quicker option than buying new.

To start the repair, I first removed the exhaust pipe from the engine, which was easily done by removing two Torx-headed bolts.

When I removed the pipe, I noticed that there was a metal gasket sandwiched between the pipe and the engine, To avoid losing it (and the bolts for that matter) I temporarily reinstalled the gasket back onto the engine, securing them in place with the bolts.

With the pipe removed, I gave it a test fit back onto the muffler, confirming that it was indeed a weld failure since the welded seam on the pip fitted nicely in the opening of the muffler.

However, a few years ago I had bought a little MAP-OXY gas welding/brazing torch on sale for around 50. Other than a quick lesson in a grade 8 shop class, I never really learned showed to weld and it is always something I want to learn how to do.

Since I am a real newbie to welding, I figure anything that I would do would look really rough, so I apologize beforehand to any welding experts for my shoddy workmanship. But since the muffler will be hidden underneath my tractor’s hood, I figure my sins will be hidden from view.

First I positioned the pipe into the muffler so that it sat into the intake of the muffler and stayed in place.

Ideally, some sort of vice would have been a better option, but since this was a driveway repair, I had to make do with what I had.

Next, I hooked up the torch, put on some welding goggles, turned on the MAP gas and I sparked up the torch.

Once the torch was going, I slowly turned on the oxygen until I got a nice Neutral flame on the end of the torch

Next, I heated the seam of the pipe and muffler with the torch until the metal glowed red and I then filled in the seam with a copper brazing rod. I keep going around the seam with the torch and rod until I could no longer see any gaps in the seam.

Like I said, it wasn’t pretty, but a couple of test hits with a hammer showed that at least the pipe was now solidly attached to the muffler.

Once the muffler cooled down, the final step was to reinstall the muffler back on the tractor by reattaching the straight pipe back onto the exhaust manifold of the tractor, making sure to have the gasket installed between the engine and the pipe and making the bolts as tight as possible.

When I started the tractor again, things were a lot more quieter. Over the course of the season, I will be keeping an eye on the muffler.

Since this is definitely a known failure point, there is a potential that I may need to do a mid-season patch up (though I hope not!), however as I have found out, it’s a pretty quick fix.

A smoking lawn mower is never a good sign. Whether the smoke is blue, white, or black, here’s how to identity and address the issue without the help of a professional.

By Glenda Taylor and Bob Vila | Updated Sep 24, 2020 1:40 PM

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Q: Recently, my mower started billowing smoke when I powered it up, so I shut it off immediately. Why is my lawn mower smoking? And is it a fire hazard? I want to know how to proceed so I don’t harm the machine.

A: Your lawn mower can emit smoke for numerous reasons—many of which don’t require the services of an expert. A homeowner can usually identify the reason for a smoking lawn mower by gauging the color of the Cloud coming around the engine, then fix it accordingly before lasting damage occurs. Keep in mind that all mowers with internal combustion engines contain the same basic parts, but the configuration of those parts varies widely, depending on manufacturer and model. Consult your owner’s manual if you’re unsure how to access a specific part of your lawn mower’s engine.

White or blue smoke may indicate an oil spill on the engine.

If you’ve recently changed the oil in your mower and the engine is emitting white or blue smoke, it’s possible that some of the oil spilled onto the engine. Similarly, you could’ve spilled oil on the engine by mowing on a slope greater than 15 degrees or tipping the mower on its side. The smoke may look disconcerting, but it’s completely harmless. Solve the problem by restarting the mower and allowing the spilled oil to burn off. If you tip the mower often for cleaning or maintenance, check your owner’s manual to determine the best way to reduce the risk of oil leaks.

An overfull oil reservoir may also cause white or blue smoke.

Ensure you didn’t overfill the mower by checking the oil level with the dipstick located on the reservoir. To do this, remove the dipstick cap, wipe off the stick with a rag, and reinsert it into the reservoir. Then remove the dipstick once again and determine the oil level in comparison to the recommended “fill” line on the stick. If the level is too high, drain the oil (consult your owner’s manual for instructions), then refill the reservoir with it. Start checking the oil level with the dipstick after you’ve added about ¾ of the amount recommended in the manual. Continue to add small amounts of oil until the level matches the recommended “fill” line. Also note that using the wrong grade of engine oil may cause blue or white smoke. Consult the owner’s manual for the exact type of oil recommended for your mower.

Black smoke may indicate that the mower is “running rich,” or burning too much gasoline.

Your lawn mower’s carburetor regulates the ratio of gasoline to air mixture. If the carburetor isn’t getting enough air, the mixture has a higher percentage of gasoline, which can create black exhaust smoke. It’s possible that a dirty or clogged air filter is preventing sufficient airflow into the carburetor. Try replacing the air filter. (Note: air filters vary by mower model; view example air filter on Amazon.) Next, run your lawn mower for a few minutes. If the black smoke still appears, the carburetor might need to be adjusted in order to increase airflow. Either take the mower to a professional or adjust the carburetor yourself with instructions in your owner’s manual.

Take your mower to a repair shop if necessary.

If the previous steps don’t correct blue or white smoke, your mower could have a more serious problem, such as an air leak in the crankshaft (the cast iron or cast aluminum case that protects the moving parts of a mower’s engine). Continuing blue or white smoke could also indicate that some of the engine’s components or seals are worn out and need replacement. Similarly, if black smoking still persists after you’ve replaced the air filter and adjusted the carburetor, you could be facing a more serious mechanical issue. All of these problems require the help of a professional. If your mower is still under warranty, check with the manufacturer for the location of the nearest servicing dealer; problems stemming from a factory defect or poor workmanship may garner free repairs. If your mower is not covered under warranty, a reputable small-engine repair shop should also be sufficient to get the job done.

Why your lawnmower is louder than usual (with fixes)

Lawnmowers have a reputation for being loud machines, but over time, a lawnmower can get louder than usual to the point where it becomes difficult to use it. While we can’t do much about the engine’s normal sound, some noises, such as grinding sounds, squeaking, and knocking, are not normal and need to be fixed. Some common reasons why your lawnmower is louder than usual include:

• Your blade assembly might be loose, which creates a loud rattling noise
• The build-up of grass and debris under the deck of the mower and on the blade can produce a loud clunking sound
• The damaged or rusted muffler can increase the sound of the engine
• Not changing the engine oil regularly can cause a knocking sound from the engine

Any unusual sound coming from your lawnmower should be looked into immediately. If your lawnmower is running louder than usual, it can also cause permanent damage to your mower and reduce its life if you ignore the noises. That is why we will tell you about the causes of why your lawnmower has gotten loud and how you can fix them.

Loose blade assembly

One of the most commonly experienced noises from a lawnmower is a loud rattling sound resulting from a loose blade assembly. If the blade assembly is loose, it will move around during startup and keep rattling as the lawnmower runs. Sometimes the blade itself can be bent or damaged, which can cause a lot of noise and put a lot of strain on the drive shaft itself.

Fixing a loose blade assembly

You can fix a loud blade assembly yourself by following these steps below:

• Step 1: Take precautionary measures: Disconnect the spark plug wire before you tip the lawnmower on its side and ensure that all power switches are in the off position. This precaution will ensure that the mower doesn’t start up accidentally when looking at the blade assembly.

• Step 2: Check the bolt tightness: Tip the mower on its side, get a wrench, and see if the bolt holding the blade is tightened up or not. If the bolt feels loose, get a piece of wood to jam the blade in place and turn the bolt clockwise until it is tight.

Note: If your blade assembly is not loose and the bolt is tight, but you still hear vibrations and rattling from underneath the lawnmower’s deck, then chances are your lawnmower’s blade is the source of the noise. If the blade is out of balance (one side is lighter than the other), you can use a mower blade balancer to balance both sides of the blade, or if the blade is severely bent or damaged, you might have to replace it.

Damaged or worn out muffler

A muffler is used to suppress the engine exhaust’s sound, reducing the engine noise significantly. But if the muffler gets damaged or is not properly sealed with the engine, the noise will not be suppressed properly, and you will hear a lot more noise coming from your mower’s engine. Sometimes, the muffler’s damage may be visible in the form of holes or cracks, while other times, the muffler may not fit properly with the engine outlet. Luckily most lawnmowers come with easy-to-remove mufflers that are relatively cheap to replace and install. You can buy a decent muffler for your lawnmower for between 20 to 40, and replacing a worn-out muffler should reduce engine noise significantly.

Fixing a damaged lawnmower muffler

Since lawnmower mufflers are not too expensive, it is recommended to replace the muffler instead of trying to fix it because even if you put some sealant on the hole or crack, it will come off in no time. Replacing your lawnmower’s muffler is a pretty straightforward task, and it can be done in a few easy steps.

• Step 1: Let the engine cool: Before starting the muffler replacement process, ensure the engine is not hot. If you have just used the mower, it is wise to wait a few hours before replacing the muffler. Wear a pair of work gloves for protection and turn the muffler counterclockwise to make it loose. Keep turning the muffler until it comes off.

Note: Sometimes, the muffler may be stuck due to rust, and to unscrew it, you will need a pipe wrench to get it unstuck. Most lawnmowers can be removed by simply turning them, but some mowers have an exhaust pipe with the muffler attached to the pipe’s end. If the exhaust pipe itself is damaged, you will have to replace it as well, which is a bit difficult compared to removing the muffler, and you might need professional help to avoid damaging your mower’s engine.

• Step 2: Buy the new muffler: Don’t throw away the damaged muffler just yet because you will need to buy a matching muffler that fits your lawnmower. So take the old muffler to the store to find a similar new muffler to install on your mower.

• Step 3: Install the new muffler: Putting the muffler back on is as simple as taking it off. All you have to do is put the threaded end of the muffler into the engine’s exhaust outlet and turn it clockwise until it is nice and tight. With a new muffler installed, your lawnmower should run quieter now.

Not changing the engine oil frequently

While lawnmower engines are small, they still require regular oil changes every 30 to 40 hours of use or twice a year. Engine oil lubricates different moving parts of your lawnmower’s engine; over time, heat and friction can burn up the oil. After a certain time, the engine oil loses its ability to lubricate the engine properly. This causes the engine’s moving parts to rub against each other, making the lawnmower louder than usual when running, and a loud knocking sound can be heard coming from the engine. Luckily some lawnmowers have a built-in low engine oil alert, which lets you know when to change the engine oil, but even if you have a mower that doesn’t have a low engine oil alert, you can easily check and change the engine oil using the method explained below:

Changing engine oil

You should change the engine oil of a lawnmower at the start of every mowing season and again during the mowing season if the mower engine starts getting noisy and the oil turns dark in color.

• Step 1: Warm the engine up: You will want to warm up the lawnmower’s engine before changing its oil because warm oil flows out easily.
• Step 2: Place an oil container: Place a pan underneath the oil fill to catch the old oil and tip the mower to its side so that the oil fill cap points downwards with the pan directly under it.

• Step 3:Drain the old oil: Now remove the oil fill cap with the lawnmower tipped to its side and let the oil drain out for a minute or two.

• Step 4: Add fresh oil: Pour fresh engine oil into the mower’s engine and make sure to pour the correct amount of oil into the engine.

Note: You can find the correct type of oil and the correct quantity of oil in the owner’s manual of the mower.

How loud is too loud for a lawn mower?

If your lawn mower is louder than usual, it will cause a lot of distraction in your society, especially if you’re mowing early morning, late evening, or weekend. If you ignore these sounds and allow yourself and your neighbors to be exposed to them for several hours, it will cause permanent hearing loss by killing some important cells inside your ears. The decibels of sound varies by the fuel, type, model, and size of your lawn mower.

Remember that humans talk at just 60 decibels and ensure that the surrounding sounds don’t exceed 85 decibels, which is harmful. I recommend installing sound measuring applications on your smartphone or using a manual sound meter. As soon as you notice that the sound of your lawn mower is over 85 decibels and you are exposed to it for over 90 minutes, it would be best if you use hearing protection. Personally, I would always wear it, also when the duration is much shorter.

If you find it challenging to use a decibel meter on your phone and don’t have a sound meter, you can also use this rule of thumb: if your lawnmower sound is such that you have to yell to talk to someone nearby, it is too loud.

Let me now categorize the average sound level of different lawn mowers based on the fuel that they run on:

• Gas-powered lawn mower: The normal sound of a gas-powered lawn mower is 85 decibels, so you must use properly licensed hearing protection if you plan to use it for a couple of hours or if you are working near a moving one.
• Electrical lawn mower: The average sound of a properly functioning and well-cared electrical lawn mower is just 75 decibels which is quite comfortable to use as compared to the gas-powered one. In the opinion of medical professionals, this level of sound will not harm your hearing.
• Riding lawn mower: This is the loudest type of lawn mower, producing over 100 decibels of sound, so exposure to it without proper hearing protection for just four to nine minutes can cause permanent hearing loss.
• Tractor: It produces 92 decibels, so you must not use it without hearing protection for 90 minutes. And if you are continuously around such a noise for eight hours, even with hearing protection, you are still at risk.
• Unpowered manual reel mower: It has no engine, so it makes minimum noise and is the safest option for those at a higher risk of hearing loss.

Ear muffs, canal caps, custom-designed ear plugs, reusable ear plugs, and roll-down foam ear plugs are all the best and most reliable ear protection gear, but make sure that they are produced by licensed manufacturers.

An alternative could be a suitable over-the-ear headset, which you can use to listen to music or a podcast while using your lawnmower.

Many states in the USA forbid homeowners to operate noisy lawn equipment before 7 a.m. or 8 a.m. and after 8 p.m. on weekdays and weekends. You will face penalties and other legal issues if you ignore these rules. Ask your neighbors if your task is unavoidable and discuss the time suitable to carry out such tasks.

Final remarks

With some care and proper maintenance, you can get rid of loud noises common in lawnmowers. Now that you know the possible causes, you can perform the necessary fixes by yourself. If anything is ambiguous or the noise persists, it is always better to consult a professional.