Toro Lawn Mower Smoking – Why And What To Do?

Toro lawn mowers are well known for their powerful engines, excellent quality, and durability. However, what if your Toro has a smoking engine? Lucky for you, we've done extensive research and have the answer for why this is happening.

The most common cause of lawn mower smoking is low oil levels or an airflow restriction. To find out what is causing the smoke, you can troubleshoot by inspecting:

  • The air filter
  • Oil levels
  • Piston ring
  • Valve train
  • Engine gasket

Lawn mowers can sometimes be erratic. When you pull the cord, the engine sputters into power, followed by plumes of smoke from the engine and beneath the mower deck. Keep reading to find out about this equipment, how to fix a smoking mower engine, and more!

Things to do when your lawn mower is smoking, Toro Lawn Mower Smoking - Why And What To Do?

How Do You Stop Your Toro Lawn Mower From Smoking?

The first indication of smoke from your Toro lawn mower might be alarming. Smoke might be a simple repair or an indicator that you have a serious problem that necessitates purchasing a new engine.

Your engine's age and how well it has been maintained might be mainly correlated to engine troubles.

Check And Replace The Air Filter

An air filter in your Toro prevents dirt and debris from entering the engine, allowing only clean air into the air intake.

When the air filter becomes clogged with dirt and grass, the engine loses access to air. Your engine could overheat and, even worse, start sucking air and oil out of the crankcase. The crankcase's air begins to burn, resulting in smoke.

Check your air filter more regularly than once a year when you service your lawn mower. Maintaining a clean filter will save you money on future engine repairs.

Check The Oil Levels

Woman checking lawn mower oil

Your Toro lawn mower engine may smoke if you do not use the proper amount of engine oil. It makes no difference whether the oil is too high or too low because both might lead to smoke.

Low-Level Engine Oil

When the engine oil level is too low, the moving components are no longer fully lubricated. As a result of friction created by the functional engine elements, your engine will generate extreme heat.

This heat can cause the engine's components to melt and smoke.

You might try to rescue your engine by adding new engine oil. When it reaches this point, adding more oil usually won't help because the heat has already caused extensive engine damage.

It would be best to take your mower to a Toro dealer for inspection.

High-Level Engine Oil

Too much oil can produce excess crankcase pressure, allowing oil to leak back into the cylinder or even up to the air intake through the valve train.

In this situation, oil enters the cylinder and begins to burn off when the engine is ignited, resulting in smoke. To solve this issue, you must remove some oil from the engine.

Check Your Piston Ring

Repairing small gasoline engines for lawnmower

Checking for oil on the spark plug is one technique to tell whether you have an internal engine problem.

Take out the spark plug. Depending on the size of your mower, you'll need a 3/4" or 5/8" socket. Remove the spark plug and inspect it for excessive oil accumulation. If you detect oil, it indicates that you have an interior problem.

Excessive oil on the spark plug indicates a piston ring or valve train issue. Either problem will require you to disassemble the engine.

A cylinder wall score may allow oil to enter and burn off in the combustion chamber. If you have this problem, you may have to choose between replacing your engine and purchasing a new mower.

Check The Valve Train

Repair of a small internal combustion engine from a lawn mower

You may have a valve train issue, but it is not always the worst. Removing the cylinder head and performing a leak down test can this be detected. A small engine mechanic should complete this task.

When a valve burns due to overheating, it can cause a valve train problem. The heat causes the valve's edge to disintegrate. This is referred to as a burned valve.

If your muffler is glowing red due to extreme heat, it could indicate that your Toro has a burned valve or a timing issue.

To make the valve seat correctly, the valve and seat must be cut at specific angles. This ensures it makes good contact with the engine block when completing the combustion chamber.

Check The Engine Gasket

View of intake and exhaust valves, spark plug and gasket on a lawn mower during tear down and servicing

If the engine gasket on a Toro mower screws up, the oil may leak onto the hot muffler. When the oil burns due to the heat from the muffler, it produces a cloud of smoke.

You must locate the damaged gasket and replace it, which can be difficult depending on where the gasket is located. Now that you've figured out how to stop your lawn mower from smoking.

Continue reading to learn what this smoke color does to your lawn mower and how to maintain your equipment for more prolonged usage.

The Difference Between Blue, White, And Black Smoke In Your Toro Lawn Mower's Engine

When it comes to engine problems, smoke is the most apparent symptom.

While it may appear to be a severe malfunction, an engine blowing smoke is often not. However, if left to its own devices, it can worsen.

Different colors of smoke can indicate various engine problems.

Blue Or White Smoke

The combustion of excess oil causes the color of the smoke.

It is best to follow the steps outlined above to determine the root cause, first checking the engine oil level and inspecting the piston rings, valve train, and engine gasket for damage.

Black Smoke

This is usually due to a problem with the carburetor or fuel system. The most common cause is an overly rich fuel-to-air mixture, meaning more gasoline is in the mix than it should be.

This could be due to one of two things: a clogged air filter or a carburetor that needs to be tuned.

How Do You Maintain A Mower To Make It Last Longer? 

An adequately maintained lawnmower will outlast a poorly maintained mower.

Remove the gasoline from your mower if it will be stored for an extended period to avoid carburetor problems and rust. To prevent rust, scrape the blades clean at least once a year, removing grass and mud.

The mower's oil, air filter, and spark plug should all be changed at least once a year.

You now have an idea of how to maintain your equipment. Now, when you replace the oil, what is the best oil you can use for your lawn mower? Is it fine to mix oil with gas in a mower? And how long does this equipment last?

When Should I Change My Lawn Mower Oil?

Change the oil in your lawnmower engine after the first five hours of use on a new mower, then at least once a year during the spring and summer mowing seasons, or after 50 hours of operation, whichever comes first.

Which Oil Is Best For A Toro Lawn Mower?

Filling oil in engine on a lawn mower

The outside temperature determines the type of oil you use.


SAE-30 is the most popular motor oil for small engines such as lawnmowers, chainsaws, and snowblowers. It denotes a viscosity rating of 30, as specified by the Society of Automotive Engineers (SAE).

The oil classification ranges from 0 to 50. Highly viscous oils perform better in hot environments or high-temperature use. If you live in a warmer climate, you should use this engine oil.

Click to see this product on Amazon.

SAE 10W-30

The SAE 10W-30 is a multigrade oil. It is multigrade because it has a variable range of viscosity. The oil's viscosity is 10 when the engine is cold and 30 when the engine is hot.

The advantage of using SAE 10W-30 is that it performs better in cold weather. However, using this grade of oil may increase your oil consumption.

If temperature differences are relevant in your area, you can use a multigrade oil.

Click to see this product on Amazon.

5W-30 SAE

SAE 5W-30 has a cold temperature viscosity value of five compared to 10W-30. This rating indicates that it is highly beneficial for cold-weather areas.

Because the viscosity of any fluid increases at low temperatures, if you live in an area where the temperature falls below 0 degrees, use 5W-30 instead of 10W-30.

Click to see this product on Amazon.

Can You Mix Oil And Gas In A Lawn Mower?

Lawnmowers usually have one of two engines. The first engine type is a two-cycle/cylinder engine, and the second is a four-cycle/cylinder engine.

If you have a two-cycle engine, you can use a combination of gas and oil. However, if you own a four-cycle engine, you must avoid mixing the gas and oil, or your engine will be damaged.

How Long Does A Lawn Mower Engine Usually Last?

Toro Titan zero turn lawn mower with bagger attached in yard of grass

The average lawnmower can last 8 to 10 years with proper maintenance and care.

A poorly maintained lawnmower may only last half as long. The number of hours used by some manufacturers determines the service life of their lawnmowers and components.

It's A Wrap

Lawn Mower smoke can cause severe concern and anxiety in people unaware of the issues caused by their mower blowing smoke. Smoke from the mower is frequently caused by minor problems that can be resolved quickly.

Allow the burning mower to run for a while if there is white and blue smoke. Smoking will usually stop after a few minutes. Otherwise, follow the directions above. In the case of black smoke, check the fuel and ensure the carburetor and air filter are in good condition.

Made it to the end? Check out these helpful related posts below:

Toro Mower Keeps Blowing Fuses – Why And What To Do?

How To Keep Grass From Sticking To Lawn Mower Wheels

Toro Lawn Mower Smoking – Why And What To Do

Leave a Reply

Your email address will not be published. Required fields are marked *