Lawnmower Air Filter Soaked in Oil? How to fix

Keeping your lawn mower’s air filter clean is very important because they protect your engine by trapping dirt and debris from the air passing into it through the carburetor. Mowing your lawn exposes the engine to dust and dirt, which can get into the engine, causing damage if the air filter is not functioning correctly. The oil can also leak into the carburetor, causing more damage. It is common to experience oil soaking up the air filter, but not to worry, this article will inform you on how oil gets into the air filter, how to deal with it, and other related information. 

The solution to fixing an oil-soaked air filter is to replace it with a new one, but depending on the type of air filter, it is possible to clean it and have it good as new again.

What Is an Air Filter, And How Does It Work?

An air filter is a relatively small part of a lawnmower but with a crucial function. They are usually made of paper or foam or a hybrid of both. The way an air filter works is pretty simple. The engine sucks in the air while in operation. This air passes through the air filter, and the filtered air mixes the gas in the carburetor. The filter prevents dirt from getting into the carburetor. It’s all part of an oxygen combustion system. For the engine of the lawnmower to work, there needs to be constant combustion, which happens with the right amount of gas (gasoline) mixing with air (oxygen in particular) and being sparked upon by the spark plugs.

lawn mower on overgrown lawn

How does an Air Filter get Clogged?

The air filter makes sure that the air getting into the system is as pure as possible. Sometimes when the spark plugs are bad, the air filter begins to get clogged with carbon soot due to bad combustion. Occasionally, the air filter gets blocked due to the debris it’s filtering out of the combustion engine, causing insufficient oxygen to reach the combustion chamber.

What Happens When the Air Filter Gets Clogged?

Insufficient oxygen means that the engine uses an increased amount of gas to overcome the poor gas to oxygen ratio. Insufficient oxygen also means an increase in carbon build-up and soot, causing a consequent amount of air pollution harmful to the environment and the user. And finally, insufficient oxygen also means that the combustion engine can get damaged or experience what’s called an engine knock with time.

The air filter on most riding mowers is located on top of the engine inside the air intake housing. It can also be found beside or under the engine in some cases. It is attached to the fuel injection system to prevent dust and particles from interfering with the combustion process. 

What Happens When the Air Filter Doesn’t Filter the Air?

This can occur as a result of a perforation in the air filter, which is more common when paper filters are cleaned inappropriately. This allows debris to find its way into the combustion engine, potentially damaging the engine.

This is why lawnmower manufacturers and repairers recommend that annually the air filter on the lawnmower should be checked and cleaned when adequate or changed. 

Types of Air Filter

There are three main air filters for lawnmowers. They are categorized based on the material used to make them. The three types are:

  1. The foam filters
  2. The paper filters
  3. The dual-element filters 

Foam Filters

It is majorly a thick slab of foam and is often coated in oil to catch debris and particles from the incoming air. An advantage of foam filters is it’s easy to clean and reuse. To clean it, simply clean with soap-dishwashing liquid or use an automotive degreaser; that should work fine. Then let it dry before placing it back. However, when it becomes worn out, it must be replaced with a new one.

Note also that some foam filters require being oiled to function effectively. Be sure to consult the owner’s manual or get a professional opinion before dipping the foam filter in oil or not.

Paper Filters

A paper filter resembles a foam filter, except that it’s made of paper. The problem is that paper isn’t as friendly with cleaning as the foam is. As a fact, many manufacturers do not advise cleaning a paper filter. Its effectiveness may reduce after you clean it, or it could get destroyed in the process. The good thing is that replacing it isn’t very expensive. So if you have a paper air filter that’s clogged, try using a vacuum cleaner at first or, better still, get it replaced.

Dual-Element Filter

A dual-element filter works by incorporating both the paper and foam filters. The foam filter functions as the primary filter, catching and trapping most of the debris, while the paper filter acts as a secondary filter dealing with debris that wasn’t caught by the foam filter. This way, it makes sure that as little debris gets into the air filter as possible.

Typically, cleaning a dual-element filter involves tapping the paper aspect of the dual-element filter on a firm surface. Whatever debris is there gets to come out on its own. Or have the paper aspect removed and replaced entirely. The foam aspect is then cleaned first with soap (dish soap with grease-cutting abilities should do the job). Afterward, the foam should be rinsed and dried with a towel or a large napkin to get the moisture out of the filter. Be careful not to squeeze the foam filter with your hands directly; it could damage it. After all these have been done, confirm from your owner’s manual or by checking your lawnmower model online to know whether the foam filter requires oil to function or not, and apply oil accordingly.

How Does Oil Get into The Air Filter?

The air filter getting soaked in oil can be caused by excess carbon deposits or sludge in the crankcase. This stops the oil from flowing properly, so the pressure causes extra oil to push through the PCV valve and into the air filter. This is one explanation for getting an air filter soaked with oil. Another one can happen when lawnmower owners oil foam air filters that should not be oiled, or they get soak the paper air filter with oil, or over oil a foam filter that should be oiled.

Irrespective of how this eventually happens, you have an air filter that’s soaked with oil and not functioning properly.

How do You Know When an Air Filter is Soaked with Oil? 

First off, if your air filter should be oiled, it needs just a little oil. You’ll know your air filter is soaked with oil because you’ll see a concentration of oil on an aspect of the air filter. If you don’t check your air filter regularly (which you should), you may notice some drops of oil where you keep your lawnmower (although this is less likely to be due to an over-oiled air filter alone). If you notice that the engine is jerking while using it (works fine but seizes at intermittent times while operating) or sputters while being used, it may be a sign that insufficient air is getting into the combustion chamber, and this can be a result of an oil-soaked air-filter.

Dealing with an Air Filter Soaked in Oil

The best way to deal with an air filter that’s soaked in oil is by having it drained as much as possible. One way to do so is to get latex gloves, wear them, and compress the air filter firmly but gently. Your aim is to remove as much oil as you can. Another method is to wrap the air filter in a towel or a napkin and gently compress the air filter within the towel. This allows the oil to seep into the towel or the napkin and saves you the trouble of staining your ground with oil or your garage.

If the air filter is both soaked and dirty, draining the air filter alone won’t do the trick. You would have to clean the air filter before oiling it again if you have to.

P.S: If the air filter that got soaked is a paper filter, your best option is to change it. Paper filters are not supposed to even touch oil at all. 

Final Thoughts

Air filters are an essential component of a lawnmower’s engine. Sometimes due to oil leaks, problems with parts of the engine, or even faults on the part of the owner, the air filter may become soaked with oil, hindering it from operating properly. In this article, we’ve explained how the air filter works, why it must work properly, the different types of air filters, how they could become soaked with oil, and how to deal with them when they’re soaked with oil.

Remember to always consult your owner’s manual before repairing your lawnmower or servicing it. Seek professional help if you’re confused at any point in time or you feel the issue at hand is bigger than you can handle. 

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