Lawn mowers are an investment, but they’re essential to keeping our yards tidy and healthy.
And to keep them in working order, they’ll need proper maintenance, from the blades to the engine.
That includes knowing how to clean the carburetor on a lawn mower.
Some signs of a dirty carburetor include black smoke, increased fuel consumption, and a stuttering or stalling engine.
To clean the carburetor, you’ll just need your chosen carburetor cleaner, some compressed air, and cleaning rags. You can find the component under your mower’s air filter.
Ready to be a mechanic for a day? Grab some gloves and let’s get to work.
What is a Lawn Mower Carburetor?
A carburetor is part of the ignition system.
It’s responsible for supplying the correct mix of air and fuel to the lawn mower engine, where the mix will ignite and provide the power.
Where is the Carburetor on a Lawn Mower?
For push and self-propelled lawn mowers, the carburetor is commonly located either on the side or the top of the engine, underneath the air filter.
Look for the filter housing, then remove it. That should expose the carburetor and air filter.
For ride-on mowers, the carburetor is also below or behind the air filter. However, accessing the carburetor on a ride-on mower is much more difficult.
If you suspect a dirty carb on your ride-on model, you might be better off taking it to a small engine repair shop.
Signs of a Dirty Carburetor
The main sign of a dirty carburetor is that your lawn mower won’t start, especially after winter.
Alternatively, if your lawn mower starts then dies, it’s not getting fuel to the combustion chamber.
Other signs that your carburetor needs cleaning include:
- Black smoke from the muffler
- Increased fuel consumption
- Poor mower performance (stuttering engine or uneven blade movement)
- Lawn mower overheating
How Often to Clean a Lawn Mower Carburetor
You should always check and clean your carburetor on its first use after winter. This will ensure there hasn’t been any damage or dirt build-up over the season.
Check the rest of your mower as well, especially the fuel line, fuel tank, oil reservoir, and air filter.
Otherwise, for regular maintenance, clean your mower’s carburetor every few uses. You can clean the mower’s air filter alongside it.
Before You Clean Lawn Mower Carburetor
Check over your mower and ensure there’s nothing else causing problems. For example, a dirty spark plug can also cause a stalling engine (and you can easily clean a mower spark plug).
Alternatively, you could have a clogged air filter, a dirty fuel filter, or poor engine fuel.
Before unscrewing anything, take the time to clean the mower and engine first. Remove any dirt and debris, and wipe the surfaces to clear off dust.
Then check the condition of your carburetor. Exposed wires, rust or corrosion, and other damage could mean you’d need to repair the parts or replace the carburetor entirely.
How to Clean a Carburetor Without Removing It
The easiest method of carburetor cleaning is to do so without removing it. This is best for people without the technical knowledge to remove and disassemble the carburetor parts.
To clean a lawn mower carburetor without removing it, you’ll need:
- Flashlight or penlight
- Screwdrivers
- Clean rags or microfibre cloths
- Compressed air
- Carburetor cleaner (look for a spray-type carb cleaner, like STA-BIL Carb/Choke and Parts Cleaner or Gumout Carb and Choke Cleaner)
- Protective equipment (rubber gloves, face mask, and eye protection)
Ensure you have a clear workspace so you don’t lose track of any parts. Wear protective equipment at all times while working.
Make sure the mower is switched off or unplugged and completely cooled down.
Start by removing the air filter housing. You may have to unscrew the fasteners and set them aside. Refer to your owner’s manual for any instructions or cautions.
Take out the air filter and check to see if it’s dirty or damaged. You can either clean it or replace it outright.
Once the carburetor has been exposed, use the flashlight or penlight to inspect the parts and interior. Check for exposed wires, corrosion, or moss.
Peek at the spark plug, too – it may have worn out.
Following that, inspect the connections from the carburetor’s throttle to the choke plates. There could be loose screws or dried gunk in the throttle cable.
Use the compressed air to blow off any built-up dirt and gunk from the carburetor. The straw or nozzle will help you get into hard-to-reach areas – just make sure to spray in short bursts, and don’t use industrial-strength compressors.
After that, take your chosen carburetor cleaner and spray it to coat the surfaces. The cleaner will help remove deposits along the air passages. It can also help clear a clogged fuel line.
Do not introduce any water, as this could potentially ruin your engine.
Use the rags or cloths to wipe away any gunk or grease. You can dampen a rag very slightly to remove solid or stubborn dirt.
Double-check that everything is in place, then put back the filter and housing. Then start your lawn mower and let it run for 5 minutes to make sure it’s running smoothly.
What If I Need to Remove My Carburetor to Clean It?
If you think you need to clean the internal components of the carburetor, then you’ll have to remove it and disassemble it.
This will let you clean everything more thoroughly, from the carburetor bowl to the fuel valve.
Unless you have mechanical experience, we don’t recommend this – you could lose track of parts or reassemble the carburetor improperly.
Removing and disassembling the component to clean it will require a carburetor repair kit, including small tools such as a nut driver and pliers.
You can also use a carburetor cleaner such as Chevron Techron Concentrate Plus or Berryman Chem-Dip Carburetor Parts Cleaner.
You can also use WD-40 on a carburetor – but specifically the Specialist Carb/Throttle Body & Parts Cleaner.
Follow your owner’s manual for disassembly. Be mindful of the gaskets and place the carburetor in a bucket to catch any excess fuel.
Use the carburetor cleaner per package instructions. Let the parts soak for an hour before rinsing them and wiping them dry (or using compressed air).
Reassemble the carburetor carefully before reattaching it to the engine. Test your mower by letting it run for 5 minutes to ensure everything is in working order.
TIP: Take photos from all angles as you disassemble the carburetor. These will help you make sure you’re putting all the parts back in the right place.
Lawn Mower Carburetor Problems – Why It Gets Dirty
One main cause of carburetor problems is stale fuel.
If you leave fuel in your engine while your mower is unused for a long time, the liquid can turn gummy or gunky – which could get stuck in the different parts.
Exposure to excess moisture (whether your lawn mower got wet or it’s been very humid) could corrode the carburetor and other parts.
A broken or malfunctioning air filter could let dirt and debris into the internal systems, clogging the carburetor and engine.
Alternatively, the constant vibration from mowing can loosen parts (such as screws or connections) over time.
And of course, overuse or prolonged use will wear down your mower parts (including the carburetor) sooner than necessary.
When to Replace the Carburetor on Your Mower
Unlike spark plugs or air filters, carburetors should never need replacing unless they’re badly damaged.
If you have no maintenance issues, you’ll replace your carburetor when you replace your mower.
Essential Mower Maintenance
Proper mower maintenance will help extend the machine’s lifespan and functionality.
Some important tasks include:
- Winterising your mower (if necessary)
- Regularly changing oil and fuel
- Keeping safe oil levels
- Cleaning or replacing the spark plug
- Cleaning or replacing the air filter
- Sharpening mower blades
- Not mowing wet grass
And yes, it also includes knowing how to clean the carburetor on a lawn mower!
Keep your carburetor clean and your mower in working order so that when mowing season rolls around, you’ll get a perfectly manicured lawn easy-peasy.
