Why Lawn Mower Smokes White in 2023 & What to Try?

lawn mower smokes white

Observing white smoke in a lawn mower is considered a normal event after using the mower for a noticeable period.

But, what are the reasons behind the lawn mower smoking white?

The reasons are the defective head gasket, excessive engine oil, imbalanced flow to the carburetor, leakages in fuel injector, bad piston rings, too much oil in the reservoir, fuel in the combustion chamber, and the overheating motor.

To be honest, you have picked the correct article that has everything regarding the lawn mower smokes white.

So, stay till the end of the article.

Why Does My Lawn Mower Smoke?

As there are several reasons, I have listed the most common ones behind the lawn mower smoke.

So, why don’t you also check their fixes from the list? 

Serial            Reasons                        Fixes
1Defective head gasketGet a new head gasket
2Excessive engine oilMaintain the engine oil level
3Imbalanced flow to carburetorAdjust the carburetor 
4Leakage in fuel injectorChange the fuel injector
5Bad piston ringsReplace the piston rings
6Too much oil in reservoirPut recommended amount of oil
7Fuel in combustion chamberSeal the fuel leakages
8Overheating motorClean or change the motor

Lawn Mower Smokes On Startup?

A mostly encountered event of white smoke is the lawn mower smokes when it is turned on.

Several reasons are behind it and you can find them with fixes from the following suggestions.

Reason 1: Defective Head Gasket

A defective head gasket is the significant culprit that can have worn seals.

Due to it, the crankcase of the mower gets in touch with the fuel from cylinders. And, we know that crankcase should not get any fuel in it. Otherwise, white smoke is fast to come.

Solution: Get a New Head Gasket

At this point, I prefer getting a new head gasket as the old one may not pair well with the fixes. So, do not get late in replacing it.

Reason 2: Fuel in Combustion Chamber

Combustion chamber has a strict restriction for fuel.

But, when the fuel units get leakages anyhow, the fuel can flow to the combustion chamber. And, fuel in there is much closer to generate white smoke.

Solution: Seal the Fuel Leakages

Inspecting the combustion chamber can let you be sure of the fuel’s presence. Clean the fuel properly and catch the leakages to secure them with a seal.

Reason 3: Imbalanced Flow to Carburetor

The carburetor getting an imbalanced flow of fuel and air is not at all recommended.

Because, more fuel or air than required or less than needed, both can cause the carburetor to burn an excessive amount of fuel or air. That’s why smoke is seen when you start the mower.

Solution: Adjust the Carburetor

The adjustment of the carburetor can let the fuel and air flow as much as required. You can do that perfectly by following the owner’s manual.

Lawn Mower Engine Blowing White Smoke?

Noticing white smoke coming from the lawn mower engine is certainly a concerning thing.

So, check out the possible reasons for it and the effective solutions.

Reason 1: Too Much Oil in Reservoir

The reservoir is always instructed to be filled with a limited amount of oil. But, many times, the mistake can happen by filling it with too much oil.

This is a road for the oil to leak through its relief outlet and reach the combustion chamber or the engine. And, burning of this oil is discovered with white smoke.

Solution: Put Recommended Amount of Oil

As you have learned about this, I hope you will maintain the amount of oil in the reservoir. Hopefully, no oil will leak anymore and white smoke will be gone.

Reason 2: Excessive Engine Oil

Excessive engine oil is never a good move for the entire mower.

Because, when you put more oil than the limitation, it can leak and reach the engine. And, this mistake leads the engine to overheat noticeably and ends up by blowing white smoke.

Solution: Maintain the Engine Oil Level

At any cost, you should never cross the limitation of oil set by the manufacturer. Maintaining it can keep both the mower and the engine safe and healthy.

Reason 3: Bad Piston Rings 

Bad piston rings are responsible for not draining the extra oil that has reached the combustion chamber.

Well, it is truly a red zone for white smoke to come often. If they have failed to function, this may continue till you notice and can harm more.

Solution: Replace the Piston Rings

I do not recommend repair for the piston rings as it is a tiring and lengthy process. Moreover, they may not serve as before. So, look for no other way than installing new piston rings.

Lawn Mower White Smoke from Exhaust?

The exhaust of a lawn mower doesn’t leave white smoke without any irregularity.

To fix this on time, get the root causes of it with the ideal remedies from this section.

Reason 1: Leakages in Fuel Injector

Is the crankcase still getting fuel on a regular note?

Then, the fuel injectors must have leakages that are allowing the fuel to go to the crankcase. Though sad, the fuel in the crankcase is an effective way to invite white smoke.

Solution: Change the Fuel Injector

In the case of the fuel injectors, there is no other remedy than changing the fuel injectors. Because, repairing them tends to leak again after a few days.

Reason 2: Clogged Oil Filter

 As the oil filter works with debris every time, it can get clogged if it is not cleaned for an extended period.

As a result, it leaves the debris with the oil and engine gets irritated with it. Thus, overheating of the engine causes white smoke.

Solution: Get a New Oil Filter

A new oil filter is the ultimate demand of this problem. That’s why you shouldn’t think twice about installing a new one for the mower.

Reason 3: Overheating Motor

An overheating motor is a noticeable reason of white smoke.

A dirty motor or using the mower without any break or cutting dense grass can pressurize the motor. As a result, it is easier to overheat and emit white smoke.

Solution: Clean or Change the Motor

You can try cleaning the motor on a regular basis and balance the pressure on it. If it is old enough, you can change the motor for better performance.

Lawn Mower White Smoke Then Dies?

You may see white smoke coming from the mower while running it but the mower stops just after that.

Luckily, the solutions of this issue are detailed with the reasons in this segment.

Reason 1: Using Wrong Fuel

Using wrong fuel is not a good act for the engine. Because the engine demands a specific type of fuel depending on the mower.

In case you put the wrong one, the engine will get overheated, smoke white and die eventually.

Solution: Get the Recommended Fuel

Check if you have used the wrong fuel. Throw that away and maintain the recommended fuel type for your particular mower model.

Reason 2: Valve Seals Not Working

Valve seals are for keeping the air and fuel away from the combustion chamber. But, over time, they can get weakened and stop working.

Also, misplaced valve seals are favorable for the fuel to reach the combustion chamber and cause white smoke in the exhaust.

Solution: Replace the Valve Seals

The only fix to this trouble is replacing the valve seals with new ones. I do not suggest repairing the seals as it doesn’t stay longer.

Reason 3: Short Circuit in Wires

Short circuit in the wires is a common reason that happens too often.

Short circuits can occur anytime and excessive current can let the electric unit or the wires to burn. As the burning goes on, white smoke is visible.

Solution: Change the Blown Wires

Checking the wires can show you brown or blown signs on them. If you get any, do not delay in changing the wires and avoid running the mower with blown wires.

Riding Lawn Mower Smokes When Blades Engaged?

Is your riding lawn mower having white smoke when the blades are engaged? 

Then, go through the following tips to repair the issue.

Reason 1: Debris in Mower Deck

The most common reason is the leftover dirt, soil, grass and debris in the mower deck. All these let the deck malfunction and pressurize the mower motor.

Consequently, due to excessive load, the motor can overheat and result in smoking.

Solution: Clean the Mower Deck

The only solution to this issue is cleaning the mower deck thoroughly. Each corner of the mower deck should be free from dirt and debris.

Reason 2: Blades are Stuck

Just as the mower deck, the blades can get anything irregular. As they are rotating, an unusual thing can get them stuck.

And, it lets the motor feel overloaded and overheats it. Thus, smoke is noticed.

Solution: Clean Around the Blades

Reach the mower blades and inspect around them deeply. Remove the unwanted materials from them and clean the blades carefully.

Reason 3: Deck Belt Not Working

Another thing that helps the motor in overheating is the deck belt that is not working as before.

It can get stretched way more than required or any damages are clearly visible in its body. All these are favorable for the motor to create smoke.

Solution: Adjust or Replace the Belt

First, you can try by adjusting the deck belt in an accurate position. If that doesn’t help, no other ways are opened than replacing the deck belt.

Is White Smoke from Lawn Mower Dangerous?

The danger of white smoke from a lawn mower can be decided by observing the density and amount of the smoke.

Light white smoke is considered harmless. Because too much oil in the lawn mower causes white smoke, the smoke can leave as soon as the oil level is balanced.

In case the smoke is coming continuously and much more densely than before, something serious has happened in the internal components. This can be dangerous for the lawn mower if ignored.

Does White Smoke from a Lawn Mower Mean Too Much Fuel? 

Answer: White smoke from a lawn mower is an indication that too much fuel has reached the combustion chamber. When the injector unit malfunctions, the fuel flows to the combustion without any limitations.

Is Light White Smoke Normal on a Lawn Mower?

Answer: Yes, light white smoke after turning on the lawn mower is considered a normal matter. During cold starts of the mower engine, you may notice this type of smoke more frequently.

End Note

In the end, I guess you also agree that various facts are responsible for the lawn mower smokes white. To be honest, the lack of our regular maintenance of the lawn mower components is a good host in this regard. 

As you have already gone through the fixes, you can surely get rid of the white smoke.

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Scott McFadden

Hi! It's Scott McFadden. I'm obsessed with farming. All my life I grew up around my grandfather and his farmhouse. I cannot put in words how they inspired me to farm. From taking care of cows to looking after our gardens I have learned a lot. It would be a real pleasure if I get to share this with you.

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