Why is My Lawn Mower Smoking?

Is your lawn mower smoking and causing you concern? White, blue, or black smoke coming from your mower can signal various issues.

Our team at Mowrator has put their heads together to provide you with effective solutions. If it turns out that your old petrol mower is nearing its end, consider our battery-powered, remote-controlled Mowrator S1 mower. All electric, zero smoke!

This article will help you identify why your lawn mower is smoking and guide you on how to fix it.

Key Takeaways

• Clean or replace the air filter and change the oil to keep your lawn mower from smoking.
• Blue smoke may indicate oil burning from overfilling, damaged seals, or a cracked crankcase.
• Carburetor issues like dirt buildup or old fuel usually cause white lawn mower exhaust smoke.
• Get professional support if DIY troubleshooting does not work.

Common Causes of Lawn Mower Smoking

Your lawn mower could be smoking for several reasons. Common causes include blocked air filters, leaking oil, carburetor or electric motor issues, and old engine parts. Recognizing the cause can help you tackle the problem quickly and get back to mowing your turf in no time.

Blocked Air Filter

A dirty or clogged air filter can create black smoke from your lawn mower. When the air filter is blocked, not enough air can mix with the fuel. This imbalance leads to too much fuel burning in the engine, which causes it to smoke.

To fix this issue, clean or replace the air filter. Avoid tipping your mower on its side while working on it, as this could spill oil into the rest of the mower – where it should not be.

Leaking Oil

Overfilling the oil reservoir can lead to oil leaks, causing white or blue smoke to billow out of the engine. Mowing on a slope can also spill oil onto the engine, which will create more smoke and possibly damage the mower.

Burning oil typically produces blue smoke. This issue often indicates worn-out seals or gaskets that need replacing. Even worse, your lawn mower’s crankcase could be cracked. Regular oil changes can prevent some leaks, but not all of them – especially those caused by mechanical wear and tear inside your engine's components. In some cases, you may need to repair the engine with professional support.

Carburetor Issues

Carburetors mix fuel and air for the engine. If it doesn't work properly, your lawn mower can start smoking. Dirty or clogged carburetors can interfere with this mixture. You might see white smoke if the level of fuel is too high.

Old fuel makes things worse. It changes how the carburetor functions, leading to more problems. Adjusting the fuel mixture can help, but sometimes you’ll need a full cleaning or replacement of parts. This is especially true if the components are old and worn out.

Worn-Out Engine Components

Worn-out engine components often lead to smoking issues. Old or failing parts can disrupt the fuel-to-air ratio and make your lawn mower smoke. Issues may stem from a blown head gasket that lets oil seep into the combustion chamber, which leads to blue or white smoke.

Always use fresh, high-quality oil to keep everything running smoothly. Moreover, incorrect oil grades make it worse. On top of that, too much oil in the crankcase ventilation system will create more issues and lead to visible smoke while mowing.

Electric Motor Problems

Electric mowers can be a real headache when they start smoking. If the electric motor is shorting across the wiring, it typically results in smoke. This happens when wires inside the motor get damaged, which results in unwanted electrical connections.

Sometimes, smoking occurs after long periods of inactivity. Dust builds up, causing friction and overheating once re-activated. Always check if any debris or dirt is blocking the air filters or blades before use.

If your mower continues smoking, it might be time for professional help to prevent further damage.

Troubleshooting and Fixes: Smoke from Mower

Turn off the lawn mower right away to cool it for at least an hour. Check for visible issues like leaks or clogged filters.

Immediate Actions

Turn off the engine right away. Safety first! Make sure you’re not on a slope and locate a flat spot to inspect your mower.

After letting your mower cool down for at least an hour, check for visible oil leaks around the engine. If you see any, do not start it again until it’s fixed. Overfull oil reservoirs cause smoking, so drain excess oil if needed. Running the mower for 5 to 10 minutes may burn off extra oil, but only do this after ensuring there’s no significant leak or damage.

Next, inspect the air filter. A blocked filter makes engines work harder and smoke more. Clean or replace the air filter if necessary. This can solve a lot of smoke issues quickly! For electric mowers, clear out any debris that might cause overheating and catch fire.

Clean and Replace Parts

1. Check and Replace the Air Filter
   • A dirty air filter blocks airflow, causing black smoke.
   • Remove the filter cover.
   • Check if it’s clogged with dirt or debris.
   • Clean it with soap and water, or replace it if it’s damaged.
2. Change the Oil
   • Old or incorrect oil type causes smoke.
   • Drain old oil by tipping the mower or using a drain plug.
   • Refill with the correct type of oil as specified in the owner’s manual.
3. Clean the Carburetor
   • A gummed-up carburetor affects the fuel mix, leading to smoke.
   • Remove the carburetor carefully.
   • Use carb cleaner spray to clean out any gunk and residue.
4. Inspect Spark Plugs
   • A worn-out spark plug may cause incomplete combustion and create smoke.
   • Remove the spark plug using a wrench.
   • Clean it with a wire brush and baking soda, or replace it if it’s too worn out.
5. Replace the Fuel Pump
   • A faulty fuel pump leads to improper fuel flow and smoking.
   • Disconnect the fuel lines safely first to avoid spills.
   • Install a new fuel pump, ensuring connections are tight.
6. Clear the Exhaust Port
   • Blocked exhaust ports prevent proper gas release, causing smoking issues.
   • Locate and carefully unscrew the exhaust port cover. Do not damage bolts.
   • Use a soft brush or compressed air for cleaning out grime buildup inside.

Adjust Fuel Mixtures

Too much or too little fuel can create excessive smoke from your lawn mower. An incorrect fuel-to-air ratio often leads to black smoke billowing from the machine. Adjusting the mixture usually involves tweaking the carburetor settings.

Find the adjustment screws on your carburetor and turn them slowly while the mower runs, until you see a clear exhaust.

Overfilled oil can hint at a faulty fuel pump. Ensure the oil levels are correct and that the pump is working correctly before adjusting any mixtures. If you’re unsure about doing this by yourself, consult a professional to save both time and stress.

When to Call a Professional

If your lawn mower keeps smoking even after cleaning the air filter and checking for oil leaks, it’s time to call a professional. Head gasket issues or piston ring problems need expert repair. Additionally, persistent smoke might mean more than just dirty parts – it could be a sign of internal engine damage.

Using the wrong type of oil can also cause smoking. If you're unsure about which oil grade to use, it's best to seek help from someone experienced. Electric motor problems are tricky, too; if your electric mower smokes, have a professional look at it immediately. It’s worth noting that getting timely help will ensure safe and efficient lawn mowing without risking further damage to your equipment.

Preventative Measures

Taking care of your lawn mower can prevent it from smoking. Regular maintenance is similar to many of the fixes we’ve mentioned above:

• Check Oil Levels: Maintain proper oil levels. Low or dirty oil can cause smoke.
• Clean Air Filters: A blocked air filter chokes the engine. Replace or clean it regularly.
• Inspect Spark Plugs: Ensure spark plugs are clean and in good condition for efficient ignition.
• Use Correct Fuel and Oil: Always use the correct grade. Wrong types can cause smoking.
• Routine Tune-Ups: Schedule regular tune-ups and inspections to catch issues early.
• Store Properly: Keep your mower in a cool, dry, safe place to avoid rust and damage.
• Monitor Engine Components: Check for wear and tear on parts like belts and blades.

Following these steps will keep your lawn mower running smoothly and smoke-free. If you need any further assistance, get in touch with our dedicated team at Mowrator. We’ve got expert advice to help you get the best out of your lawn mower.

FAQs on Why is My Lawn Mower Smoking?

Can a Dirty Air Filter Cause My Lawn Mower to Smoke?

Yes, a clogged air filter can make your engine work harder, leading to smoke. Clean or replace it.

Is White Smoke from My Lawn Mower Serious?

White smoke often means burning oil, which could indicate an internal problem like worn rings or seals.

What Should I Do If My Lawn Mower Starts Smoking Suddenly?

Stop using it immediately. Inspect for issues like fuel mix problems, blocked vents, or overheating parts.

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