Why is my lawnmower smoking? 20 Things You Should Know

Even after using your Lawnmower without any problems, it can suddenly surprise you. One of the more popular problems happens when you pull the cord, and the engine pops into action, followed only by clouds of rising smoke from the engine and from beneath the mower deck. What is happening, and what should you do to solve this problem?

Puffing smoke is usually not a severe malfunction, but it can worsen if not handled with care. Do not panic! We have made a troubleshooting guide to moving steadily and carefully from one stage to the next. Many reasons may contribute to this problem, but the fault is mostly due to fuel leakage from the exhaust.

Why is my lawnmower smoking?

The most probable cause is oil spillage from the tank when you are changing its oil or filling it beyond the proposed level.  Moreover, turning/tilting the carburetor engine down during maintenance, loading, or any other cause may also contribute to this problem. When you are moving uphill, or downhill it will cause oil spillage.

Other causes include:

1. Filling the crankcase with oil beyond its limit
2. Any obstruction in the breather tube, which is present at the back of the air filter
3. Worn out the crankcase breather
4. Blown head gasket
5. Damaged or impaired cylinder rings
6. Usage of wrong engine oil grades
7. An engine tilted to an angle greater than 15 degree
8. Air leakage from the crankcase

Most of these reasons are easy to fix, and in this blog post, we will help you with tips that will resolve your issue. Just follow the steps as we relate them to different colors of smoke.

Why is my lawnmower smoking?

● White and blue smoke:

White and blue smoke shows that the engine is consuming excess oil due to some reason. Stay peaceful if your mower is smoking because it is not any complicated issue. Lawnmowers generally produce white or blue smoke when fuel is overfilled, and it oozes into the crankcase. Damaged piston rings and low-quality oil are also reasons for the smoke.

Follow the given detailed steps to get rid of white and blue smoke:

– Step 1. Check the level of oil:

Overfilling of engine oil or usage of unsuitable engine oil grade can be a reason for both clouds of smoke. Follow the given steps to check the level of oil.

• Take out the stick after opening the dipstick cap
• Please clean it
• Please put it in oil again
• The level of oil must be between two holes on the dipstick but if the oil is overfilled, use the owner’s manual to learn how to drain the oil

– Step 2. Adjust the tilting angle:

Ensure that the tilting angle of the engine is not more than 15 degrees. Mowing uphill can cause oil spillage into the combustion chamber, so in this scenario, the spark plug is facing upward to prevent oil leakage.

– Step 3. Inspect oil leakage in crankcase:

Check the crankcase for leakages and seal them as soon as possible.

– Step 4. Use the right oil:

Always use good quality oil and inspect which grade oil suits your Lawnmower. Never overfill the oil as it can cause many issues.

– Step 5. Examine rings, cylinders, and head gasket:

Examine if the cylinders, rings, and head gaskets are impaired or damaged. If it is so, replace them as they can’t be fixed.

An Important Tip: When you start a new mower, it will give white smoke. There is no need to worry in this scenario due to residue left behind in the mower by the manufacturing company. In this case, let start the engine until the entire residue is burned.

– Preventive measures:

Mostly thin white smoke vanishes on its own when we allow the engine to run for some time- as it is not a matter to worry a lot. However, the emission of profuse white smoke can be a signal towards a big issue. For instance, this issue occurs when oil made its way into the combustion chamber and then creates trouble for the engine to work well.

• Oil is used for lubrication purposes, but if you add more oil than suggested, then it would ooze into other parts where it should not be. When the Lawnmower is turned on, the engine starts emitting white or blue smoke by burning that seeped oil. Therefore, it is imperative to prevent oil leakage.
• Keep your spark plug in an upward position to prevent this issue even when moving uphill.

However, on the positive side, such issues can be solved quickly.

● Black smoke:

Black smoke shows that there is some problem in the carburetor and fuel system. It indicates that there is burning of more fuel than air, i.e., the oil mixture contains more gasoline than the mandatory amount. It is due to a faulty carburetor or dust and debris stuck in the air filter. Black smoke in the Lawnmower may also be due to debris in the air filter, which causes clogging or an un-cleaned carburetor.

Follow the given detailed steps to get rid of black smoke:

– Step 1. Locate Air filters:

First, localize the position of air filters.

– Step 2. Clean the air filters:

After detaching, use soap, water, and detergent to clean them. You may use an air gun, if available, to blow air for thorough cleaning. If the stuck debris is not cleaned, i.e., the air filter is blocked, replace it with a new filter as they are not so costly. (Paper filters can’t be cleaned. They can only be replaced).

– Step 3. Fix the air filters:

Now test the mower. If it still produces black smoke, then follow the next step, and if not, you are good to go.

– Step 4. Adjust the carb:

Consult the owner’s manual to fix the carburetor by twisting its screw. Adjusting the carburetor will make a composed fuel-air mixture. Check and adjust the carburetor to make a thinner mixture if the black smoke persists.

– Step 5. Inspect the choke and reinstall:

The air-fuel mixture will be rich in gasoline if the choke is facing some problem. Therefore, check the choke’s connection and require repairing and ensuring that it is free of debris. Look up the manual for adjustment purposes. Generally, it comprises two screws outside the unit one is for the idle, and the other is for the fuel mixture.

If the mower continues to emit black smoke after following the given steps, some intricate issues should be addressed to professionals.

● Excessive smoke:

After following the steps mentioned above, the mower is still emitting excessive black smoke. It indicates that oil reaches the combustion chamber through some damaged seals, and it can make your engine dead, which is a grave issue. This issue may be due to a

• Blown head gasket or worn-out breathing tube.
• The damaged piston ring.

The piston ring prevents the movement of fuel between the cylinder and piston wall, and if it has damaged it, it will surely be the cause of the smoke. Generally, three pistons are used in a mower engine. Therefore, if any of the three rings were damaged, it will leak fuel from the cylinder to the combustion chamber, burning and emitting white smoke. Faulty or damaged fuel and air filters will allow the dust into piston rings, which damages them.

Methods to stop your Lawnmower from blowing smoke:

• Quantity of oil: Observe the quantity of oil in the engine. Overfilling will cause emission of smoke.
• Flat environment: Try always to keep the mower on flat or level ground. This decreases the likelihood of any possible tilt and leakage of oil.
• Righ oil grade: It would be best if you always used the right engine oil grades. You can also know the sort and quantity from the Lawnmower’s owner’s manual.
• No air leaks: Ensure no air leaks on the crankshaft are present.
• Head gasket check: Regularly check the head gasket, rings, and cylinder and ensure that they are in good shape.
• Air filter: Inquire and replace the air filter.
• Mowing angle: Check the angle at which you are mowing. An angle greater than 15 degrees can cause the Lawnmower to smoke.

One thing that matters a lot is the color of the smoke. It may be white, black, and blue. In an ideal World, these colors indicate peace, stability & depth, authority, and power, respectively. However, these colored emissions have a new meaning for Lawnmower blowing smoke, and they might indicate troubling equipment. Suppose you are not acquainted with the mechanical components and do not precisely know where the troubleshooting problem is. In that case, this article will help you understand how to fix the smoky Lawnmower without consulting a professional.

Frequently asked questions:

1. Why is oil coming out of my lawnmower exhaust?

Oil can leak into the exhaust system if the piston rings are damaged or if you turn the engine on its side. If you have had the engine turned over, the oil may burn after running the engine for a while. If it continues to seep from the muffler, then you need a ring job.

2. Can too much oil cause white smoke from exhaust?

If profuse, white smoke comes out of the exhaust pipe, there is too copious oil in the engine. This may also be due to antifreeze burning, so it is best to take the carb to the mechanic because any of the smoke causes can be disastrous for the carb.

3. Why is my Electric lawnmower smoking?

The smoke comes from the motor’s connection and a little plate pushed by springs that connect to the bridge rectifier. The metal immediately between the motor and the plate turns red hot and starts smoking. It only smokes on the positive side of the motor connection.

Final remarks

Engines of lawnmowers may be designed differently, so you must go through the owner’s manual before proceeding through any hacks or techniques. A simple trick is to check our mowers’ smoke color and try to fix it before taking it for repairs. We hope you are now well acquainted with avoiding engine oil problems and with stopping a lawnmower from smoking. Have an enjoyable time in the sun mowing and all the best.