The Top 4 Reasons Your Lawn Mower is Smoking

If your lawnmower is smoking, it is an obvious indication that something is wrong. We have put together a quick list to help you get your lawn mower up and running at peak performance again. Be mindful, that whenever you are performing any type of engine maintenance, that the engine needs time to cool, the spark plug needs to be disconnected, and it is recommended to always consult with the owner’s manual for detailed instructions for your specific engine.

Reason # 1: Too Much Oil

Lawn mowers require oil to avoid overheating while in use. Oil also provides lubrication, ensuring a smooth and efficiently running engine. If there is not enough oil, this can cause friction between parts, and this can also lead to overheating. When there is too much oil in your lawnmower it will be hard to start, and this will cause the engine to work harder than it needs to. This can lead to over-heating, smoking, and oil leakage. Oil leakage is also very dangerous, as this is a fire hazard, and needs to be rectified immediately. Check your oil level and make sure you have the proper amount. To avoid putting too much oil in your lawn mower, refer to your owner’s manual to know how much oil it needs to run efficiently.

Too Much Oil - Top 4 Reasons Your Lawn Mower is Smoking

Reason # 2: The Carburetor

The carburetor brings fuel and air together and mixes them at the correct ratio to allow for proper combustion. If there is an issue with your carburetor the mixture may be off. Too little fuel could cause damage to your engine, and too much fuel could lead to carbon build-up, causing a smoking engine. Performing regular maintenance on the carburetor is essential for a smooth-running lawn mower. Most carburetor issues are due to a blockage from dirt, varnish, or gasoline deposits. Remove the carburetor and give it a good cleaning. When cleaning, be sure to target the main fuel jet (located in the fuel bowl nut) with carburetor cleaner and compressed air. This will loosen up any debris and should help get it back up and running properly. Carburetor specific cleaner dissolves deposits, which can greatly reduce premature issues. Replace any worn or damaged components, as necessary.

The Carburetor - Top 4 Reasons Your Lawn Mower is Smoking

Reason # 3: The Air Filter

Dirty air filters are a common cause of a smoking lawnmower. The air filter has the very important job of preventing dirt and debris from reaching the engine and ensuring the proper airflow that it requires to run properly. After a while, dirt and debris can plug up the air filter and restrict the amount of air delivered to the engine. Not enough air means too much fuel, which could be causing the engine to smoke. The air filter is a high-wear part that should be removed and cleaned or replaced at least every three months to keep your lawn mower running smoothly. Replacing the air filter is generally a very simple repair that should only take a few minutes to complete. For most lawn mowers, you will need to remove the air filter cover, and just pull it out by hand, line-up the new air filter to the base, and reassemble the cover.

Dirty Air Filter - Top 4 Reasons Your Lawn Mower is Smoking

Reason # 4: Piston Rings

Piston rings are what form the seal between the piston and the cylinder wall. If either of these components becomes worn, oil can leak past the rings into the combustion chamber. This will cause your engine to smoke. To avoid this, make sure your air and fuel filter are clean. If they are dirty or missing altogether, dirt can find its way into the combustion chamber, wearing away the rings and the cylinder walls. Also, check your oil. Dirty or low oil levels won’t lubricate the engine properly, leading to piston and cylinder wear.

Piston Rings - Top 4 Reasons Your Lawn Mower is Smoking

By performing these regular inspections, cleaning, and replacements, it will save you from having to make much more serious and expensive repairs down the road. It will also extend the life of your lawn mower, optimize fuel consumption (saving you money!), and improve its overall performance. For more repair and maintenance tips, check out our YouTube channel!