Lawn Mower Dirty Air Filter Symptoms

Estimated reading time: 5 minutes

We refer to the engine as the heart of any power mower. If we want to talk about its lungs, we usually think of the air filters. It is not very difficult to understand the purpose of air filters. As we need oxygen to breathe, the engine needs it in a similar way. Air filters clean out the dirt, grass, and dust particles from the air and prevent them from entering inside the internal parts of your lawnmower. 

Air filters get dirty after a while, and it is a common practice to change them to make no impact on your engine’s performance. But the question is, what is the right time to clean or change them before it is too late? Your mower won’t speak and tell you itself or give you a notification on your smart device. It is your duty to pay attention to the symptoms and decide when you need to take action. 

Lawn Mower Dirty Air Filter Symptoms

Like every other combustion engine, lawn mower engines also rely on getting air to perform well. We all are aware of how bad it is for your engine when it starts letting the dirty air in. It will be a lot easier to avoid any such scenarios when you know what to look for. Following are the common symptoms to look at and know if your mower air filters are clogging:

Symptom 1: Engine Losing Power

The lawnmower owners are very well aware of the sound it makes. When it is in good condition, it makes the purring sound. It is a matter of concern when you see the sound of your mower changing. It is a simple process in when the air filters get dirty, it decreases the flow of air and hence affects the power. Filters, when clogged with oil and dirt, choke your engine and declines the air from flowing properly. The lesser the air gets in, the lower combustion it will create in the engine, and it will lose power. Therefore, it is a clear sign for your air filters to be changed. 

Symptom 2: Issues In Mower Starting 

Your mower starts on three main factors and they are air, consumption of fuel, and spark. If any of these are not providing a sufficient amount, your mower will find it hard to start the engine every time. When the mower is coated with dirt or oil, it will create problems in the combustion process of the engine. Therefore, when you see your mower is making issues while starting, check your air filters and take them out to clean them. It usually happens when you have not cleaned or changed the filters for a while. 

Symptom 3: More Fuel Intake

It is necessary to inspect how much fuel your engine is consuming. If everything is fine, it will give you the best mileage, and when it is not the case, that is surely a symptom that something is not going well. Your air filters contribute significantly to your lawn mower’s fuel consumption. Similarly, a dirty filter can decline the mileage, and it will start running out earlier. Therefore, when you see the mower is asking for gas before the expected time, it is a symptom of the dirty air filters. 

Symptom 4: Black Smoke

When oxygen finds it difficult to reach through your engine, it will not burn the fuel in an optimal way. It disrupts and disturbs the ratio of gas and air. A higher proportion of gas with respect to the air will end up giving black smoke out of your machine. It is a bad symptom as it also affects and adds to environmental pollution. Therefore, you should pay attention when it happens. It is common for people to panic as it is a symptom of different severe problems. Instead of freaking out, take out your air filters and fix them, and it will solve the problem. 

Symptom 5: Oil Dripping 

It also happens that your lawnmower starts dripping the oil out of your exhaust pipe. It usually happens when you do some repair to your mower and then turn it over. The reason is that your air filters soak the oil, and then it becomes impossible to perform like before, or worse, it will not start. Oil dripping is not good for your mower as well as your lawn grass. It can pollute the grass when you use the mower. Oil dropping is the issue that usually occurs when you do something wrong while repairing. Keep that in mind when you are turning your mower over; keep the air filters facing upwards. 

How to Fix?

When you see the symptoms that are mentioned above, it means you need to fix them instead of going any further. All the parts connect in harmony with each other and result in the overall performance of your engine. When one starts working improperly, you will see every other part creating issues one after another. 

When you feel any symptom of a dirty air filter, do not stress yourself. Air filters are not so complicated part and are easy to clean or replace. When you see the filters dirty yet still intact, you do not necessarily have to replace them. You can clean them unless there are any holes or tears in the fabric. But, when the oil soaks in the fabric, this usually tears the fabric or get cracks on your filters. Then, it is better to change them. They are easily available in the hardware stores nearby. 


Following are the lawnmower dirty air filter symptoms that can have an impact on your mower’s overall performance. Just like you need air to live, your mower needs it in a similar way. When you identify any of these symptoms, get them cleaned or replaced without making any further delay. Running the mower with dirty or damaged filters will cause you inconveniences in long-term use. 

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