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Lawnmower White Smoke

Lawnmower White SmokeThe white smoke coming out of a lawnmower is not an uncommon issue reported to date. If suddenly your lawnmower starts to blow out any color of smoke more than usual it is time for you to stop using it immediately because it might harm the engine – in a worst-case scenario, it might seize the engine – of your lawnmower.

Lawnmower White Smoke

There are numerous reasons why this happens according to the situation. We will try to list down all possible reasons why it happens and how to resolve them at the earliest to start using your lawnmower once again without any hassle.

How Does The Lawnmower Work?

Although all lawnmower differs in appearance from model to model. They all work on some basic principles. They have a four-cycle engine that is quite similar to an automobile engine. The engine runs on gasoline with a separate sump for oil. To start the lawnmower you hold down the veils and grab the rope to start the engine. All lawnmowers have a carburetor attached to them the carburetor can be cleaned by simply detaching it from the lawnmower and they often need to be replaced as they are worn out.

Most parts of the lawnmower can be replaced easily and you find them online or even buy them from your nearest stores. In both cases, you will need the model number of your lawnmower to purchase a compatible device. You need to keep in mind that the lawnmower and engine usually have separate model numbers. To find the separate parts of your lawnmower you will need the exact model written on it.

The lawnmower white smoke is the most repeated query generated on the internet and the main cause –in most cases – is that your oil reservoir is neck-to-neck. This causes the engine to burn the oil when you start your lawnmower and you see the white smoke in your garden. If your tilt the lawnmower too much, this can also happen. If you fill your crankcase, way too much you can also see the white smoke.

There are several reasons and you need to figure out yours in your situation.

The Reasoning For Lawnmower White Smoke:

1.) Air Filter:

The very first possible reason why your lawnmower is blowing white smoke is the dirty or clogged air filter. Now, the lawnmower works when a perfect amount of air and oil are mixed-up together. If there is too much oil and the air is not sufficient it will result in the white smoke coming out from the lawnmower.

How To Recognize?

The very first thing you need to do here is open the air filter by removing the cover from it. If the problem lies in the air filter, you will see oil dripping over. If you see the oil here, the problem lies within your air filter.

By analyzing a few things, you can avoid this happening in the future. If your lawn is not healthy; you are not watering it enough and it is mostly drought. This stirs up more dirt, which means more work for the lawnmower and you are not cutting grass properly or you are cutting it way too much. All these reasons build up and affect the lawnmower’s air filter.

How To Fix It?

Once you have figured out the problem here we will guide you on how you can resolve this issue.

If your air filter is clogged up with dirt or oil, it will not be able to breathe properly for obvious reasons. This also means that the tube for the breather will not be able to breathe either. The fix for this problem is very simple, we can say that this is not even a fix it is more of maintenance.  You need to simply remove the air filter and replace it with a new one. And that is all.

It is healthy for your lawnmower to replace its air filter every few months to avoid a situation like this in the future.

2.) Oil Proportions:

The second reason we have here is the proportion of oil in your lawnmower. As we said earlier too, the proportion of oil and air here matters the most and if the quantity of both is increased or decreased, it will result in white smoke.

All lawnmowers require a constant supply of lubricants to keep them from getting overheated and damaging themselves. Too much oil in the crankcase can also damage the engine and you need to remove the excessive amount of oil inside before you can use the lawnmower again.

How To Recognize?

You can easily check the amount of oil in your oil reservoir by the oil dipstick. It will give you a reading of your oil amount and it will also indicate if it is too little or too much at the moment. If your oil amount is exceeding the limit on your dipstick this indicates the reason for white smoke coming out of your lawnmower.

The lawnmowers come along with manuals so check the amount of oil your lawnmower requires. Most of the lawnmowers require around 16-20 fl. Oz. of high-quality engine oil with 30 SAE classification. If you keep this thing in mind, it will eventually help you to get rid of the excessive amount of oil you might be adding to the engine.

How To Fix It?

If there is already too much oil in your crankcase, you need professional help. However, you can unscrew the oil fill tube attached to the crankcase and drain out as much oil as possible. When you are trying to drain it out, tilt the mower to its side. That helps with the carburetor to always tilt in an upward direction and oil will not enter your carburetor or combustion chamber.

Once you are done with the draining process, be ready for the cleanup process. You need to clean excess oil spilled over during the draining process, if not the oil can enter the either combustion chamber or the carburetor, and then your engine will start having running issues.

3.) Piston Rings:

The last one on our list here is the piston rings. They are known as the seal between cylinder walls and pistons. If excessive smoke is coming out of the exhaust, damaged piston rings can be a reason. Usually, when the piston rings or cylinder walls are broken or at fault, the oil will seep into the combustion chamber. Once it is inside the chamber, the engine oil will burn and then be exhausted. Unfortunately, if this happens, the engine will require a rebuild.

How To Recognize?

You need to check if the air and oil filters are clean. If nothing is wrong with the above-mentioned methods, piston rings might be at fault and they are being the reason for this smoke. If it is confirmed that your piston is the reason, you need to remove and replace them with new ones.

How To Fix It?

It is highly recommended that you seek professional help to solve the piston rings issues. Nevertheless, here is an easy way to do it.

You need to find the opening of the ring and put your finger against the backside of it and you will need a special tool it is called the Ring Expander. Now, put the tool on, squeeze it a little bit and the ring will come out. Now, you need to repeat this process to get all of the pistons rings off your cylinder.  Now, the next part is to clean all the grooves with utmost care. Once you are done with the cleaning process of your grove, put the rings back on and put them back inside your lawnmower.

If you do not have the Ring expander at home and you do not want to invest in this tool, you can try taking the rings off with the help of your fingers. This might take a bit of your time and you need to be very careful while doing this at home. Another factor here is that the rings are very delicate and there is a high possibility that in this process of taking them on and off you might break them. In addition, you can’t take them off individually and you have to take the set off every time.

If we compare the prices of both; ring and the tool. Rings are three times more costly. Therefore, you can make your choice between both and choose it to resolve the issue at hand.


The lawnmower white smoke is a very common issue in most mowers. It does not matter if your lawnmower is a new one or an older version of new additions. The root cause of this is mostly maintenance issues and components issues that are bound to happen no matter what lawnmower you have. These technical issues can be avoided even before they can happen, but if they did happen, you need to take care of them immediately to avoid further damage to your lawnmower.

Tom Hanks

Tom Hanks is a DIY lover and an expert of tools to give you detailed unbiased reviews and guides on using and buying great tools for your DIY projects.

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