Why Is My Lawn Mower Smoking? 4 Causes and Solutions Explained

Asking yourself why is my lawn mower smoking? Don’t worry, you’re not alone. Lawn mowers can emit smoke for various reasons, and it’s common for homeowners to encounter this issue. Often, these occurrences don’t require the services of an expert, and with a little troubleshooting, you can identify the cause of the problem and take appropriate action.

The color of the smoke coming from your mower can help diagnose the issue. In general, black smoke indicates an overly rich gasoline-air mix, which can result from a clogged air filter or a malfunctioning carburetor. On the other hand, blue or white smoke usually points to burning oil, which can result from overfilling the oil tank or an engine leak. Understanding the reasons for the different types of smoke will help you determine the necessary steps to address the problem and get your lawn mower back to proper working order.

Keep in mind that in some cases, a smoking lawn mower can simply be due to spilled oil during maintenance or a temporary issue that resolves itself after a short period of use. However, consistent or excessive smoking may indicate a more serious problem requiring professional attention. In this article, we’ll explore several common causes of a smoking lawn mower and their respective solutions to help you get your equipment back to optimal performance.

Identifying the Type of Smoke

When your lawn mower starts smoking, it is essential to identify the type of smoke to determine the underlying issue. In this section, we will discuss the three common types of smoke – white, black, and blue.

1.White Smoke

White smoke usually indicates oil burning within the engine. This could be due to an overfilled oil reservoir, oil spilled onto the engine, or the lawn mower being used on steep slopes. To resolve this issue, you can try draining some oil out if the reservoir was overfilled, or letting the oil on the engine burn off if it was spilled during maintenance.

2. Black Smoke

Black smoke typically signifies a combustion problem resulting from a dirty or ill-adjusted carburetor or a clogged air filter. You can attempt to clean the air filter, but if the issue persists, consider taking your lawn mower to a professional for a thorough carburetor cleaning or replacement.

3. Blue Smoke

Blue smoke occurs when oil leaks into the combustion chamber, possibly due to worn or damaged engine components or bad oil seals. In this case, it is recommended to consult a professional repair service, as engine repairs can be complex and may require specialized knowledge and tools.

Remember to always work on your lawn mower when it is turned off and cool to avoid potential injuries. By identifying the type of smoke coming from your smoking lawn mower and following these tips, you can help ensure the smooth operation and longevity of your equipment.

Common Causes of Smoking Lawn Mowers

1. Dirty Air Filter

A common cause of a smoking lawn mower is a dirty air filter. The air filter protects your engine from dirt and debris and ensures proper airflow for smooth operation. Over time, dirt and debris can clog the filter, restricting airflow and resulting in a smoking mower. To fix this issue, you should inspect and clean your air filter regularly. If the filter is a foam type, wash it with warm soapy water and let it dry before reinstalling. For a paper-type filter, tap the filter against a hard surface to remove dirt or replace it if it’s excessively dirty.

2. Oil Spill or Overfilled Reservoir

Another reason your lawn mower might be smoking is due to oil spills or an overfilled oil reservoir. Too much oil in the engine can cause it to burn, leading to white or blue smoke. To address this problem, first, make sure your mower is on a level surface. Check the oil level using the dipstick and drain any excess oil if needed. If you’ve spilled oil onto the engine or other components, wipe it up with a rag and allow it to dry before using your mower.

3. Faulty Carburetor

A dirty or ill-adjusted carburetor can also cause your lawn mower to smoke. If the carburetor has blockages, it can prevent the proper mixture of fuel and air from entering the combustion chamber. You can often resolve this issue by cleaning the carburetor with carburetor cleaner and adjusting its settings. If you’re unsure how to clean or adjust your mower’s carburetor, it’s best to consult your owner’s manual or take your mower to a professional repair shop for assistance.

4. Problematic Spark Plug

A faulty or damaged spark plug can lead to a smoking lawn mower. Spark plugs are essential in igniting the fuel-air mixture within the combustion chamber, so a problematic spark plug can cause incomplete combustion, resulting in smoke. Inspect your spark plug for signs of wear or fouling, and replace it if necessary. It’s also essential to check the spark plug gap and ensure it’s within your mower’s specifications, as an improper gap can lead to sputtering and smoke.

Remember that regular maintenance and troubleshooting of your lawn mower, such as cleaning the air filter, checking oil levels, and inspecting the carburetor and spark plug, will help prevent smoking issues and keep your mower running smoothly. If you’re unable to resolve the problem yourself, it’s a good idea to seek the assistance of a professional lawn mower repair shop.

How to Fix a Smoking Lawn Mower

1. Air Filter Cleaning or Replacement

A dirty air filter might be causing black smoke from your lawn mower. To fix this issue, locate the air filter on the side of the mower, usually housed in a plastic box that’s screwed or clipped into place. Remove the air filter and clean it using compressed air to clear any debris blocking the airflow. If the filter is in poor condition, consider replacing it altogether. It’s crucial to maintain a clean air filter to ensure proper operation and avoid any unnecessary smoke.

2. Managing Oil Levels

If your lawn mower is smoking due to an overfilled oil reservoir, start by checking the oil level with a dipstick[. Drain any excess oil and make sure to consult your mower’s manual for the correct oil type and capacity. If oil has found its way onto the engine, let the mower run until the oil burns off harmlessly. Also, make sure you’re mowing at angles less than 15 degrees, as greater angles can cause your lawn mower to smoke.

3. Carburetor Adjustment or Cleaning

A clogged or improperly adjusted carburetor can also be a source of your lawn mower’s smoking problem. A simple first step is to use a carburetor cleaner spray to remove any debris or buildup present. If the issue persists, it may be necessary to adjust the carburetor settings or seek assistance from a small engine repair shop.

4. Spark Plug Inspection and Replacement

Your mower’s spark plug plays a vital role in the engine’s overall performance. Inspect the spark plug for any signs of wear or damage, and if necessary, replace it with a new one to ensure proper ignition and fuel combustion. Keep in mind that spark plug issues may be covered by your mower’s warranty, so be sure to check before making any replacements.

By following these guidelines and regularly performing maintenance on your lawn mower, you can keep it running efficiently and avoid any unwanted smoke. Remember to consult your mower’s manual for specific details and recommendations tailored to your model.

When to Seek Professional Assistance

It’s important to recognize when it’s time to seek professional help for your smoking lawn mower. If cleaning or replacing the air filter, spark plug, and checking the oil levels don’t fix the issue, there might be more serious problems at hand.

Often, a smoking lawn mower may indicate issues with the oil seals in the engine lubrication system, or around the pistons¹. A cracked crankcase could also be another possible cause. In these situations, it’s best to consult a professional.

Before visiting a repair shop, check if your lawn mower is still under warranty. If it is, contact the manufacturer or the retailer you purchased it from. You might be eligible to get repairs done at no cost or at a reduced price.

A small engine repair professional will have the expertise and experience needed to diagnose and fix the problem accurately. They can ensure your lawn mower is in proper working condition and extend its lifespan. Trying to repair complex issues on your own may void the warranty or cause additional damage – especially if you’re not familiar with small engine repair.

To find a reputable repair shop, ask for recommendations from friends, family, or read online reviews. Make sure the shop and its technicians are experienced in dealing with your specific lawn mower brand and model. This way, you can be confident that your smoking lawn mower will be in good hands.

Preventing Future Lawn Mower Smoking Issues

Regular Maintenance

To prevent future lawn mower smoking issues, it’s essential to regularly maintain your lawn mower. This includes oil changes, air filter replacement, and blade sharpening to ensure optimal performance. Proper maintenance can prevent issues such as clogged filters, inadequate lubrication, and wear on the piston rings, which could lead to smoking problems.

Monitoring Oil Levels

Keeping an eye on your mower’s oil levels is crucial for avoiding smoking issues. Check the oil level, grade and type specified for your mower, and change the oil if necessary. Overfilling, using the wrong oil type, or not adding enough oil can lead to improper combustion in the combustion chamber and smoking problems. Maintaining proper oil levels helps reduce the risk of fire hazards and keeps your mower running smoothly.

Keeping the Working Area Clean

One of the reasons your lawn mower might smoke is due to oil or debris being present on the engine, often caused by tipping the mower while cleaning it or performing other maintenance tasks. To prevent this, always ensure a clean working area by removing grass clippings and debris from the mower after use, and avoid tipping the mower at angles greater than 15 degrees.

Here are some additional tips to prevent lawn mower smoking issues:

• Make sure the fuel mixture contains the appropriate ratio of gasoline to air for efficient combustion.
• Check the air filter regularly and replace it if it’s dirty to ensure your mower has proper airflow.
• Inspect the combustion chamber for signs of excessive oil or debris, which can lead to smoking problems.
• Always use the proper grade and type of oil recommended by your lawn mower’s manufacturer to ensure adequate lubrication and reduce wear on the piston rings.
• Routinely examine your mower for any signs of damage or wear that can impact its performance and potentially cause smoking issues.

By diligently following these practices, you can keep your lawn mower in good working condition and significantly decrease the likelihood of smoking problems.