Symptoms of a Dirty Air Filter
Troubleshooting for your small gas engine

An air filter is a small but mighty part on your outdoor power equipment that helps to keep your engine clean. The filter blocks dirt, dust, and debris from entering the carburetor and engine. Without the filter, all that gunk would get pulled into the internal parts of the engine, causing it to work harder, use more fuel, operate less efficiently, and eventually cause it to fail. Filters are generally made of paper, foam, or a hybrid and are designed to trap extremely small particles. It is important that you regularly inspect the condition of the filter and clean or replace it as necessary. The engine still needs air in order to operate, so while a filter helps trap debris, if it gets too clogged up it also prevents air from reaching the engine.

In this article, we’ll be talking about the symptoms of a dirty air filter and how it impacts your small gas engine. Feel free to follow along with the video, and continue reading below.


Increased Fuel Consumption

If you find your equipment is using more fuel than usual to get the same amount of work done, check to see if the air filter is dirty or clogged. Your engine has to work harder to operate since it isn’t getting the amount of air it needs. An imbalance of fuel and air can also result in black smoke coming out of the exhaust, which is another indication that the engine isn’t getting the necessary air.

Trouble Starting

A small gas engine needs the right amount of air, fuel, and a spark to start. If one of these elements is missing, there won’t be combustion and therefore your engine won’t start. So, if you have good fuel and your spark plug is fine, but your engine still won’t boot up, then there is an issue with getting the air. A clogged-up air filter is likely the culprit.

Power Loss

When the air filter is dirty it reduces airflow into the engine. Without the right amount of air in with the fuel, there’s less combustion and less horsepower. If you notice that your engine is surging up and down or even stops completely while operating, you once again want to check the air filter. If it is dirty or clogged, clean or replace it.

Symptoms of a Dirty Air Filter: Increased Fuel Consumption

Replace Your Filter

Check with your owner’s manual for the recommended filter for your specific model. An incorrectly sized filter will allow for dirt and debris to get past, and into the internal engine components. A proper fit prevents that from happening, and purchasing an OEM part is your best bet for that.

If your equipment has a paper filter, you can gently tap it on a solid surface to remove some of the debris. Hold it up to a bright light – if the light is blocked, then it is time to replace that paper filter. Unfortunately, they can’t be cleaned, but they are easy and inexpensive to replace.

If you have a foam filter that is in good shape, it can be cleaned and put back into your equipment. However, if it is crumbling, stained, or otherwise damaged it is best to replace it.

Symptoms of a Dirty Air Filter: Filter Comparison

Clean Your Filter

As mentioned above, a paper filter can’t be washed, but a foam one can! Warm, soapy water, a zip-top bag, and a bit of engine oil is all you’ll need. First wash the filter in your sink or a washtub with warm water and some dish detergent, to remove the dirt and grease. Make sure it is rinsed thoroughly, squeeze out any excess water, then leave it to dry. Before you place the filter back in your equipment, it will need to be saturated with some clean engine oil. To reduce the mess, put the filter and oil in a plastic bag and work the oil into the foam. Blot up any excess oil with some paper towel, and you’re good to go.

Symptoms of a Dirty Air Filter: Foam Type Filter

As you can see, clean and properly sized air filters are an extremely important part of making sure your small engine functions efficiently! If you need replacement filters, we have you covered. Be sure to follow along with our YouTube channel so you don’t miss any of our tips.