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Why is My Lawn Mower Smoking? Fix it in 5 Steps Immediately

Is your peaceful weekend lawn mowing interrupted by alarming smoke from your mower?  If so, you’re probably worrying about costly repairs or replacements. But don’t panic just yet! In this guide, ‘Why is My Lawnmower Smoking,’ I will dissect the possible reasons for this problem and give you simple troubleshooting steps.

From oil leaks to overfilled tanks and from faulty carburetors to stale fuel, this guide got it covered. This guide saves you unnecessary stress and expense by empowering you with the knowledge to diagnose and fix these common issues yourself.

A smoking lawnmower can indicate problems like overfilled oil, clogged air filters, or worn-out piston rings. To address it, follow troubleshooting steps like draining excess oil, cleaning or replacing the air filter, and using fresh fuel. Regular maintenance and preventive measures can prevent smoking issues. Seek professional help if the problem persists.

Common Reasons for a Lawn Mower Smoking

There are several reasons for lawn mower smoking. Some of the possible causes include:

Overfilled oil reservoir

Excessive filling of the oil reservoir may lead to oil leakage into the combustion chamber, emitting smoke in shades of blue or white.

Blocked air filter

Checking air filter if lawn mower smoking
Checking air filter for lawn care maintenance

Clogged filters are another reason for smoking lawnmowers. If the air filter is blocked with dirt and debris, air will not reach the engine, and it will restrict airflow to the engine that, causes the engine to run rich and produce black smoke.

Worn-out piston rings

The piston creates a seal between the piston and the cylinder. If worn or damaged, oil can leak into the combustion chamber, producing white smoke.

5 Steps to Fix a Smoking Lawn Mower

If your lawn mower emits smoke, it typically indicates an underlying issue requiring prompt attention. Here are some recommended steps to address and resolve the problem effectively:

1. Draining excess oil

Lawn mower smoking

Please ensure that you check the oil level in your mower regularly. If the oil is overfilled, it can lead to smoke emissions. Find the oil drain plug and position a container underneath it. Remove the plug and let the extra oil drain until it reaches the level indicated in the owner’s manual.

2. Correcting the tilt of the lawn mower

Make sure your lawnmower is placed on a leveled surface. If the mower is tilted, too much oil may leak into the combustion chamber, which may cause smoke. Adjust the position of the mower to get rid of smoking.

Related Post: 5 Tips to Mow Your Lawn Like a Professional ‎

3. Cleaning or replacing the air filter

Lawn mower smoking
Cleaning air filter to get rid of the blockage

Another reason for a smoking lawn mower is a dirty or clogged air filter that can restrict airflow to the engine leading to smoking. To address the problem:

  1. Begin by removing the cover of the air filter.
  2. Carefully extract the air filter and conduct a thorough examination.
  3. Clean the filter diligently or opt for a replacement if it appears dirty or shows signs of damage.

4. Replacing the Fuel

If you change the fuel a long time ago or are using contaminated fuel, it may cause smoking and other engine issues. Empty the fuel tank and dispose of the old fuel properly; refill the tank with fresh & clean fuel, preferably one with the correct fuel-to-oil ratio as the manufacturer recommends.

5. Repairing or replacing worn-out piston rings

If the smoking issue persists after following the previous steps, it may indicate worn-out piston rings. This repair requires more expertise and tools.

Getting an expert opinion is always wise when dealing with persistent problems you need help fixing. They’ll be able to conduct a thorough assessment of your lawn mower and give you the best guidance on how to proceed with the repairs.

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Preventive Maintenance to Avoid Smoking

Properly maintaining your lawn equipment is crucial to keep it working effectively. Here are some preventive maintenance steps you can take to avoid smoking:

Regularly checking and changing the oil

Checking oil level for lawn mower smoking

Proper lubrication is important for the engine’s smooth functioning and preventing overheating. Regularly checking the oil level and adhering to the manufacturer’s recommended schedule for oil changes is crucial. Old or dirty oil can increase friction and excessive heat, which may cause smoking.

Tip: To ensure optimal fuel preservation for durations exceeding 30 days, it is advisable to incorporate a fuel stabilizer into the system or, as an alternative, completely drain the fuel.

Ensuring the mower is stored and used in the correct position

When storing your lawn mower, make sure it is kept in an upright position. Tilting the mower incorrectly can cause oil to leak into the combustion chamber resulting in smoking when you start. Similarly, always operate more on level ground to prevent oil from spilling into the wrong areas.

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Regularly cleaning or replacing the air filter

Cleaning or replacing air filters is another important part of maintenance to improve its efficiency and lifespan.
Tip: Make sure the foam pre-cleaner is cleaned every 25 hours. During the season or after 300 hours of operation, replace the paper air filter.

Using fresh, high-quality fuel & oil

Stale or low-quality fuel can negatively impact engine performance and cause smoking. For the best results, use the right type of fresh fuel & oil on your lawn mower and follow the manufacturer’s recommendations regarding its fuel type and octane rating. Read my detailed guide on Different types of lawnmowers and which one you should opt for.

Checking for worn-out parts

You should inspect your lawnmower regularly and replace any frayed or damaged parts, like spark plugs, ignition cables, and gaskets, as soon as possible. Replacing faulty components as soon as possible is crucial, as they can affect combustion efficiency and result in smoking.

Related Post: Do I Need to Change the Lawnmower Blades?

When to Seek Professional Help?

Knowing when to seek professional help for lawnmower issues is important to ensure proper repairs and avoid further damage. Here are two factors to consider:

Recognizing signs of serious damage

While preventive maintenance can help prevent most issues, there may be instances when your lawnmower requires professional attention. Here are some signs that indicate serious damage:

1. Excessive Smoking

If you’re experiencing excessive smoke from your lawnmower, it’s essential to take action immediately. Even with proper maintenance, continued smoking can indicate more significant underlying issues. 

The engine, fuel system, or other critical components may be damaged and must be addressed promptly. Ignoring the problem could lead to more significant and costly repairs, so it’s best to address the issue as soon as possible.

2. Loss of power or poor performance

If your lawnmower experiences a notable decline in power, difficulty starting, or erratic running, it could indicate a more serious problem. Issues such as malfunctioning carburetors, ignition problems, or engine impairments may be the underlying causes of these symptoms.

3. Unusual noises or vibrations

If your lawnmower produces unusual noises like grinding, banging, or rattling, or vibrating excessively during operation, it could indicate mechanical problems that require professional attention.

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Evaluating the cost-effectiveness of repairs

When considering whether to seek professional help, it’s essential to evaluate the cost-effectiveness of repairs. Here are some factors to consider:

1. Age and overall condition: If your lawnmower is on the older side and has many problems already, it might be better to shell out a ton of money for extensive repairs. You have to look at the mower’s overall condition and consider whether it makes more financial sense to fix it up or get a new one altogether. 

2. Cost of repairs vs replacement: If the repair costs for your lawnmower are expected to be quite high or close to the price of a brand-new mower, it might make more sense to replace it altogether.

3. Warranty coverage: It’s wise to review the terms and conditions of your lawnmower’s warranty to determine if any repairs are covered. It’s usually best to get professional assistance to prevent invalidating the warranty.

4. DIY capability: Knowing your limits is essential if you’re working on a repair task and need more confidence in your mechanical skills or the necessary knowledge. Certain repairs require specialized tools or expertise you might not have. In these situations, it’s best to contact a professional for assistance. 


A smoking lawn mower can be a frustrating issue to deal with during mowing seasons. However, understanding why your lawnmower is smoking and implementing the right solution can help you overcome it and enjoy a smooth smoke-free mowing experience.

I explored this problem’s potential causes, including an overfilled Oil reservoir, a clogged air filter, worn-out piston rings, etc. You can solve these issues by checking the oil levels, cleaning or replacing the filters, and ensuring a proper maintenance routine.

Regularly inspecting and cleaning your mower, using the right fuel and oil, and avoiding overworking it on hot days can go a long way in maintaining its performance and preventing smoke-related problems. To maintain a healthy, smoke-free lawn mower, it is important to provide proactive care and timely troubleshooting. 


Can overfilling the oil reservoir cause my lawnmower to smoke?

Yes, if you have accidentally overfilled your lawn mower, it can cause smoking. Due to overspill, it can enter into a combustion chamber or exhaust system, which leads to incomplete combustion and, eventually production of smoke.

How can old or poor-quality fuel lead to a smoking lawn mower?

Old or poor-quality fuel can lead to a smoking lawn mower in a few ways. First, the fuel can evaporate over time, leaving behind deposits that can clog the fuel lines and carburetor. This can prevent the engine from getting the fuel it needs to run properly and lead to smoking. Second, old fuel can lose potency, meaning it doesn’t burn as efficiently. This can also lead to smoking, as the engine must work harder to ignite the fuel. Finally, poor-quality fuel can contain contaminants that can damage the engine. This can also lead to smoking, as the engine cannot run properly.

Can a smoking lawn mower cause any safety hazards?

A smoking lawn mower poses various safety hazards, including fire hazards, inhalation of toxic fumes, reduced visibility to see obstacles in the vicinity that can lead to accidents such as collision with obstacles or people, can contribute to air pollution, etc.

Should I turn it off immediately if my lawn mower starts smoking while in use?

Yes, you should turn off your lawnmower instantly if it starts smoking while in use. Smoking can be a sign of a serious problem with the engine, fuel leak, or improper combustion, and continuing to use it could cause fire or other safety hazards. 

Can I still use my lawn mower if it’s only occasionally smoking?

It’s generally not recommended to continue using a smoking lawn mower. Even if smoking is infrequent, it can still indicate an underlying problem that may worsen over time. It is best to address the smoking issues by inspecting and repairing the lawn mower or seeking professional help to ensure its safe and efficient operation.

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