Avoiding Fuel-Related Problems
Your Honda lawn mower is designed and manufactured to precise specifications to ensure years of troublefree operation. This includes the fuel system. However, the properties of gasoline can quickly lead to stale fuel causing starting or running problems and, in some cases, damage to the fuel system if precautions are not followed. The good news is most fuel-related problems can be avoided by following a few simple steps. The steps shown below are also recommended for Honda-powered lawn mowers.
Follow These Five Steps to Prevent Most Fuel-Related Problems
Do not use gasoline containing more than 10% ethanol in your Honda lawn mower.
Gasoline containing higher levels of ethanol is corrosive and attracts water, which can cause starting or running problems or, in some cases, damage to your lawn mower’s fuel system.
Store your gasoline in a clean, plastic, sealed container approved for fuel storage. Close the vent (if equipped) when not in use and store the container away from direct sunlight. If it takes more than 3 months to consume the fuel in the container, we suggest adding a fuel stabilizer to the fuel when you fill the container.
A clean, plastic container approved for fuel storage will help prevent rust and metallic contaminants from entering the fuel system. Gasoline will deteriorate faster when exposed to air and sunlight.
Keep your lawn mower’s air filter properly serviced. Check it before each use.
A properly maintained air filter will help prevent dirt from entering your lawn mower’s carburetor. Check the filter before each use. Replace it often when used in dusty conditions. Dirt entering the carburetor can be drawn into small passages in the carburetor and premature engine wear. These small passages can become blocked, causing starting or running problems. Always use a Honda Genuine air filter to ensure the air filter seals and performs as designed.
When you’re finished mowing, turn the fuel valve OFF and leave it OFF until you’re ready to mow again. Fill the fuel tank to minimize air in the tank. If you do not intend to use your mower for 3 to 4 weeks, start the engine with the fuel valve OFF, and allow it to run until the engine runs out of gas.
The small amount of gasoline in your lawn mower’s carburetor will deteriorate faster than the fuel in the fuel tank due to its small volume and proximity to residual engine heat. The fuel valve allows you to stop the fuel flow from the fuel tank to the carburetor for storing and transporting.
Filling the fuel tank after each use (instead of before each use). If the fuel tank is partially filled, air in the tank will promote fuel deterioration.
If you don’t plan to use your lawn mower for more than 30 days, follow the storage guidelines below.
Untreated gasoline (without a fuel stabilizer) left in the lawn mower’s fuel system will deteriorate, causing starting or running problems and, in some cases, damage to the fuel system.
Refer to your lawn mower’s Owner’s Manual for additional information. If you do not have an owner’s manual, you can download the manual here.
Storing Your Lawn Mower for Than 30 Days
If you don’t plan to use your lawn mower for more than 30 days, follow these steps to reduce fuel-related problems.
Storage Time: 30 to 90 days
- Add gasoline stabilizer to the fuel tank following the manufacturer’s instructions. When adding a gasoline stabilizer, fill the fuel tank with fresh gasoline. If only partially filled, air in the tank will promote fuel deterioration during storage. Note:
- All stabilizers have a shelf life, and their performance will deteriorate over time.
- Fuel stabilizers will not reconstitute stale fuel.
- After adding a gasoline stabilizer to the fuel for the first time, run the engine outdoors for 10 minutes to be sure the treated gasoline has replaced the untreated gasoline throughout the fuel system. If you regularly add fuel stabilizer to your storage container when refilling, you may skip this step.
- Stop the engine and turn the fuel valve to the OFF position.
- Restart the engine and allow it to run until it runs out of gas. Running time should be less than 3 minutes.
After adding a gasoline stabilizer to the fuel for the first time, run the engine outdoors for 10 minutes to be sure the treated gasoline has replaced the untreated gasoline throughout the fuel system. If you regularly add fuel stabilizer to your storage container when refilling, you may skip this step.
Stop the engine and turn the fuel valve to the OFF position.
Restart the engine and allow it to run until it runs out of gas. Running time should be less than 3 minutes.
Storage Time: than 90 days (long term or seasonal storage)
Start the engine and allow it to run long enough to empty all the gasoline from the entire fuel system (including the fuel tank). Do not allow gasoline to remain in your lawn mower for more than 90 days of inactivity.
Stale fuel in your fuel container
If you have some fuel left in your storage container at the end of the season, the Environmental Protection Agency (EPA) suggests adding the gasoline to your car’s gas tank provided your car’s fuel tank is fairly full and the fuel is appropriate for your vehicle.
You’re Probably Not Changing Your Lawn Mower’s Air Filter Often Enough
It’s critical that your lawn mower can breathe easily to run properly and last a long time. Therefore, you must either clean or change your lawn mower’s air filter often. How often? That depends on the size of your lawn mower and the size of its air filter, but it ranges from once a year to once a month.
How often should you change a walk-behind mower’s air filter?
Walk-behind mower engines under 10 horsepower usually have a 5-inch by 7-inch filter or paper air filter. You’ll want to swap this every 25 hours of mowing, but make certain its not clogged at least once a month.
Ironically, the tiny filter on many small mowers requires more maintenance than the larger filters on larger mowers. Because dust and grass can easily clog up one of these filters and starve your engine of air, I like to give them a quick visual inspection every time I mow. Luckily, you can often find these attached to the carburetor and view them by simply pulling off the engine shroud.
If your walk-behind mower has a small paper filter, you can remove it and try to knock the dirt off of it. According to the Power Outdoors website, you can check whether a cleaned air filter is safe to run by holding it up to the light and seeing if any light shines through.
Some walk behind mowers have an upgrade: a similarly-sized foam filter. While this filter may clog up just as often, you can wash it out with water and dish soap. Simply take it inside, wash it like a sponge. If it is not excessively dirty or torn, you can dry it and reinstall it. Note: after a foam filter has dried, you will want to rub a little filter oil onto it.
Rare walk-behind mowers have a paper filter filament wrapped in a foam pre-cleaner. You can wash this pre-cleaner like any foam filter, and maintaining it will help your paper filter last longer.
How often should you change a lawn tractor’s air filter?
Larger lawn tractors tend to have a circular paper air filter wrapped in a sponge pre-cleaner. Its a good idea to swap out this paper filter once a year or after 200 hours of mowing. But you’ll want to wash your pre-cleaner after 100 hours of mowing, or when it’s dirty.
Lawn mower engines in the 12-17 horsepower range often have a filter with both a paper and sponge element. This is so you can do many hours of mowing in one season without buying a new, large paper filter. But to maintain this filter, you will have to wash the pre-cleaner throughout the season.
How often do you have to wash this pre-cleaner? It depends on how much debris you’re mowing through. It’s a good idea to examine it weekly until you get an idea of how quickly it clogs. No matter what, you’ll want to replace this paper filter at the beginning or end of every season.
How often should you change your riding lawn mower’s air filter?
Large riding lawn mowers, with engines over 18 horsepower, often will have a canister or air intake box with a filter inside. You can probably get away with doing 250 hours of mowing before you need to replace your filter, but you will need to clean it at least every 100 hours.
Powerful, ride-on mowers often have an air filter set up much more like you’d find on a passenger car than what you’d find on a walk-behind mower. This increased capacity means you can operate the mower for 10 times as long as a walk-behind before replacing the air filter. That said, if the mower has a sponge pre-cleaner you must wash that whenever clogged to preserve your paper filter.
Remember, if your pre-cleaner is ripped or excessively dirty, then you must replace it. In addition, if your paper filter is so soiled you can’t see light when you hold it up to the sun, you must replace it as well.
Next, read our extensive lawn mower service schedule. Or, see for yourself how to change a lawn mower air filter in the video below:
How to Clean an Air Filter on a Lawn Mower
Most lawn mowers are rugged machines that can run for years. But don’t make the mistake of thinking just because a mower is running, that means it’s performing well. Often, that’s not the case. Maintenance is crucial to keeping your mower running optimally, and I recommend that most homeowners complete annual maintenance twice a year – in the spring to get your mower ready for the season, and in the late fall to winterize your mower and prepare it for storage. Today, I’ll explain how to clean an air filter on a lawn mower, and why you absolutely need to do it regularly.
I’ll also explain why annual replacement of your mower’s air filter is a simple, low-cost DIY project anyone can (and everyone should) do.
Why Your Mower’s Air Filter is Important
The air filter is one of the most important parts of your lawn mower when it comes to day-to-day performance.
If your mower starts but isn’t cutting grass properly, or seems to get bogged down easily there’s a good chance the air filter is causing the problem.
All combustion engines need air to function, so sucking in air is an essential part of the process.
Problems happen if dirt and debris gets pulled into the engine along with the air. When this happens it can lead to failures and your lawnmower not starting.
Air filters prevent this issue by allowing air to pass through to your engine while blocking all the debris, such as grass clippings, twigs, sticks, leaves, dust, and dirt.
Still, all air filters become dirty or blocked over time (that just means they’re doin their job). When they get dirty and clogged less air gets to the engine, causing problems. That’s why keeping your mower’s air filter clean is an important part of mower maintenance.
The good news? Cleaning or replacing an air filter is one of the easiest mower maintenance tasks.
Depending on your type of mower, the air filter could be located on the side or top of the engine, and it will be pretty easy to recognize.
In all models, the filter is easy to access, though it may be behind a plastic cover.
Usually it has a single screw-on or snap hinge cover holding it in place.
Below, I’ll explain what you need to know about how to clean and replace your mower’s air filter.
I’ll talk about air filter types, how to find out which kind your mower has, where to find the filter, and how to clean it.
Types of Lawn Mower Air Filters
There are several different types and styles of air filters used in lawn mowers, and it’s important that you identify what kind of air filter your mower uses so you can clean and service it properly.
Usually mowers have either a:
Below I’ll tell you a bit about each type of mower air filter.
Paper Air Filter
A paper filter looks like a paper accordion. It works by having perforated paper with tiny holes in a folded construction.
Air can pass through the microscopic holes, but debris cannot.
While you may be able to clean your paper filter, you’ll definitely need to change it for every 25 to 50 hours of mowing use.
On my self-propelled Honda mower, the paper air filter is located on the side of the mower’s engine under a rectangular plastic cap that is pressure-mounted and easy to remove.
The filter inside is just held in place with the housing, so I take out the filter, shake it gently and blow air across the paper fins to remove any big debris particles prior to use.
A replacement paper lawnmower filter costs about 8 and you can find one that will fit at just about any local hardware or big box store.
TIP: If your mower is difficult to start, you can remove the paper air filter and spray Gumout starting fluid into the hole behind the filter just before you mow. Once you’ve sprayed some in, replace the air filter and casing and start up your mower with the pull cord. This will help your mower start up easily and will also keep your carburetor clean and free of corrosion. One can will last you a few years.
A “foam only” filter works in a similar way to paper but has a different filtration material. A foam piece coated in motor oil traps all types of dirt, dust, and debris.
The motor oil is an important part of the system because it stops the smallest of dirt particles. Without motor oil, the foam filter will only capture the largest debris, and you’ll end up with a dirty carburetor that needs to be removed and cleaned.
If your mower has a foam air filter, it is essential to re-coat the filter with motor oil every three months or 25 hours of use.
Combination filters are the best air filters in the mowing world because they combine foam and paper elements to keep your engine running clean.
The foam acts as a pre-barrier for the paper element, helping to add more life to the paper (which is more expensive to replace).
Because air passes through two layers of filtration, it is significantly cleaner when it reaches the engine.
How to Replace a Lawn Mower Air Filter
Replacing a lawn mower air filter is simple and easy.
- Locate the air filter housing on your lawn mower. The location will depend on the mower type. For example, on a tractor mower you will need to lift the engine cover, while a walk-behind mower usually has the engine exposed. The air filter is typically on top, on the front, or the side of the engine, located in a plastic or metal housing.
- Open the housing by either unscrewing the lid or opening a hinge, depending on your mower.
- If your lawn mower has a foam pre-filter, remove it, and inspect it. Sometimes cleaning the foam and re-covering it in motor oil is fine. However, if the foam has become stained, brittle, or hard, it needs to be replaced.
- Moving on to the main filter. If your air filter is paper, give it a gentle tap to remove excess dirt. If the paper is blocked, then the filter must be replaced. To check, hold the filter up to a light or the sun. For foam air filters, again check for staining, hardness, or general disrepair before replacing it.
- Dispose of the old air filter.
- Insert your new air filter into the housing after cleaning the assembly.
- Reattach any protective layers and then close the housing lid. During the entire replacement process, be careful not to damage or pinch the new air filter. Any holes in the filter will allow large debris to pass into the engine.
Replacing Different Types of Lawn Mower Air Filters
As well as foam, paper, and mixed filters, it’s also worth noting that some air filters are reusable while others are disposable.
What this essentially means is that you can clean some filters for reuse, while others must be replaced and cannot be cleaned. In fact, doing so may degrade their performance and put your mower at risk.
In general, paper air filters are disposable and foam lawn mower filters are reusable.
You can gently blow on and partially clean off a paper air filter mid-season, but I don’t recommend using compressed air on them – if it looks too dirty to function well, just buy a new one for under ten bucks.
It’s a small price to pay to keep your mower working well for years to come.
Why Air Filter Maintenance is Important
Your lawn mower won’t run (for long) without an air filter.
Engines need air but cannot deal with the debris and other items that may end up lodged inside if there’s no filter.
Air filters do all the dirty work to ensure your lawn mower runs seamlessly. However, occasionally you need to clean or replace the filter.
If enough debris gets into your engine, it’ll get clogged and won’t perform as it should.
That’s why regularly replacing the air filter is a wise move if you want to your mower to perform well for years to come.
When to Change the Air Filter on Your Mower
A common question is how often the air filter on a lawn mower needs to be changed. Most experts recommend that you check your mower’s owner manual for specific guidance that applies to your specific mower.
But you’re on the internet looking for the answer you need now.
How often you need to change the filter on your mower can depend on a variety of factors, such as how often you use your lawn mower and in what conditions.
Needless to say, mowing three times a week in a dusty location is going to mean you need to change the air filter more frequently.
And when you’re mulching leaves in your yard there will be more dust kicked up and your filter will be working overtime.
Most homeowners can usually get away with changing their filters once a year. This means changing the filter around every 25 to 50 hours of use.
Whether you have a foam filter or a paper one, you can replace it with a new one by yourself, and it will take you 15 minutes (and probably much less) in your garage.
Replacing my paper air filter requires no tools and about 20 seconds of my time (including throwing the old one in the trash).
My best advice is to replace your filter annually, and visually inspect it before every mow.
Clean Your Lawn Mower Air Filter Regularly, Replace Annually
Time goes by quickly, so make sure to keep track of when you last changed your mower’s air filter.
As part of my spring mower maintenance I always install a brand new air filter in my mower.
But if you haven’t changed or cleaned your mower’s air filter, it’s a low-cost and easy fix to get your mower running like new again.
Hopefully this article has given you the information you need to keep on top of it going forward!
Lawn Mower Air Filter is Soaked in Oil: Why How to Fix
Your air filter is super important in ensuring your gas mower runs smoothly. It’s there to let the right amount of air into the engine, without also letting in dirt and grime that could impair its performance and potentially cause long-term damage.
So if yours is absolutely soaked in oil, you can probably guess that it’s not going to do its job right, and that it’s not something you can just leave to “wait and see what happens”. Things are not going to improve. In fact, it’s quite likely that your mower is not going to run at all until you take action.
A lawn mower air filter soaked in oil will have to be removed and then replaced with a new one 95% of the time. With foam filters, it might be possible to clean it.
Lawn Mower Air Filter Soaked in Oil: Here’s What to Do
Before we get into the weeds, I will just say that you shouldn’t freak out if you find your air filter is soaked in oil. Yes, it is a bit of a mess. But your mower is not ruined, and it really is quite an easy and affordable fix. Here’s what you’re going to want to do:
Safety First – Always
Any time you’re doing some maintenance on your mower, you should always take certain precautions. Here’s what I recommend:
- If you’ve been using it, let it cool down – laying your hands on a mower if the engine is still hot from running is a bad idea. Leave it outside for a few minutes and let it cool off before you start work.
- Disconnect spark plug – This is so important and might save your fingers someday. As long as the spark plug is connected, there’s always a chance the mower could fire up. It shouldn’t, but in theory, it’s possible. Make it impossible by disconnecting the spark plug now.
- Wear gloves– This isn’t an absolute must, but when I’m going to come into contact with any chemical – oil, gasoline, etc – I prefer to put some thin protective gloves on. Latex gloves work well.
Now…Dealing with that Oil Soaked Filter
Air filters in lawn mowers are not all the same. They vary from manufacturer to manufacturer, but in general, there are two main types. And the steps you should take do depend somewhat on which type of filter your mower uses.
Paper Air Filters
If you’re dealing with a paper filter, it’s simple. You have just one choice – to replace it. There’s no way you’re cleaning a paper lawn mower air filter soaked in oil. Don’t even try. You probably have more chance of digging to the earth’s core with a shovel.
If you have some replacement filters on hand, great. If not, you’re going to have to get some. I’d always recommend going with the manufacturer-specific ones as opposed to the “universal” ones that are sold. They generally work better IMO.
While you don’t need to do anything to the filter itself other than fit it, you are going to want to clean any oil from the casing. You’re probably going to want to remove the air filter housing and remove any oil from the carburetor opening too. Become sometimes, even when you replace the filter, your mower won’t start. And it’s normally because oil is blocking the carburetor. If you spray a bit of carburetor cleaner into the throat of the carburetor, and then try to get your mower going, this will often clear the rest. Don’t be alarmed if you see black smoke coming out of the mower for a while. That’s just the oil residue being burnt off.
Foam Air Filters
There’s a small chance – and it is a small chance – that you might be able to salvage your filter if it’s made from foam. It really depends on how bad the situation is.
But to not be wasteful, it’s always worth trying to clean a foam filter that’s soaked in oil before you wave the white flag and go out and buy a new one.
The process is super simple.
- Knock off any debris. This will be hard if it’s super soaked, but if you haven’t changed/cleaned your filter for some time, there’s likely going to be a buildup of debris on the top side of the filter. Knock this off while you’re still outside, or into a garbage bin.
- Take it to the sink. Now you’re going to want to take the filter to a sink and you’re doing to use some good old hot water and dishwashing liquid. Give it a thorough clean, trying to get all of the oil off. If you manage to do that, rinse it to remove all of the soap.
- Squeeze out all of the moisture. Once you’re done cleaning, give the filter a really good squeeze to drain as much of the moisture out as possible. On the final squeeze, it can be helpful to wrap it in some paper towel, as this helps soak up even more of the water.
- Leave it in the sun. Now it’s just a waiting game. You need to let the filter completely dry out. And the best way to do this is to leave it in the sun.
If you do all of this and it comes out clean – you’re golden. You can now just add some oil to the filter (yeah – kind of ironic given the topic we’re covering here, but foam filters do need to have a small amount of oil soaked into them), reseat it back into its casing, replace the cover and you’re good to go.
If you attempt to clean your air filter, but the oil just isn’t coming out and it remains clogged, you’re going to want to source a replacement (as with paper filters, I would advise you to go with a manufacturer-specific one if you can), clean out the casing and fit the new filter.
Other Things to Check If Your Air Filter is Clogged with Oil
If you remedy the oil soaked air filter, but you still have issues with starting your mower afterward, there are a few other things you can check. I would advise you to do these things anyway to be honest, since it’s possible other parts of your mower might have been compromised, especially if you determine the cause of your oil problem as being your mower was tipped on the wrong side.
If the combustion chamber is flooded with oil and/or gas, it’s possible that the spark plug may be contaminated. You’re going to want to remove it and give it a quick clean with a soft wire brush, And do make sure you use a soft brush, as harder wire brushes may damage the porcelain insulator around the electrode. And that wouldn’t be very clever!
After you’re done cleaning it, leave it to air dry before replacing it.
The other fairly common reason why your lawn mower might not start after an oil problem is that oil is either completely or partially blocking the carburetor. You’re going to need to try and remedy that.
There’s an easy/lazy way (which I touched on a bit earlier) and then a harder/more involved way. If you’re like me, you’ll probably try the lazy way first and then go for the other option only if necessary.
Okay, so you’re going to need some carb cleaner for this. All you’re going to do is spray some of this in the throat of the carburetor, and then you’re going to attempt to start your mower. If you can get it started, this will usually clear the rest. It might not run as smoothly for a few minutes, but should sort itself out the longer you run it.
If this doesn’t work, you’re going to need to remove the carb to give it a more thorough cleaning. This is definitely more involved, and if you’re not someone that likes to play around with these sorts of things, you might want to ask someone with a bit more knowledge/experience.
Most Common Causes of a Lawn Mower Air Filter Soaked in Oil
There are a few different potential reasons why you might find yourself staring down at a lawn mower air filter soaked in oil. We’re going to run through them quickly below.
Turning Your Mower on the Wrong Side
This might be a revelation to some of you, but there is in fact a right way and a wrong way to tip your lawn mower. And an oil soaked air filter is what can happen if you tip your mower the wrong way. It’s a mistake that I see time and time again, particularly among those that don’t have too much experience with mowing the lawn. They tip their mower over to tighten/sharpen/change their blade, and halfway through find a messy surprise.
The position of the air filter can vary depending on the make and model of mower that you have. But when you tip it on its side, the air filter should always be pointing upwards. If it’s pointing downwards, you’ve got the gas and oil up in the air, and gravity is going to do the rest.
Mowing on Extremely Sloped Land
Now this doesn’t happen often and won’t apply to most people, but I have heard of it being responsible for oil leaks in mowers, so thought I’d mention it. If you have grassy slopes to mow that have a pretty steep gradient, it’s possible that while you’re mowing, the angle the mower is positioned at can cause oil to move out of the crankcase (by our good friend “gravity” again) and start to make its journey toward the air filter.
You Put Too Much Oil in Your Mower
Most residential mowers don’t require huge quantities of oil. The crankcases are generally pretty small. But if you overfill it way past the recommended level, the chances of oil spilling out of the crankcase are MUCH higher. It’ll usually get as far as the cylinder, and you’ll see some black smoke (quite an alarming sight), but sometimes it might get as far as the carburetor and air filter (if you overfilled it to a stupid level).
So whenever you’re adding oil to your mower, add very small amounts and use the dipstick to measure the current level. Keep adding small amounts until it’s within the range that is recommended by the manufacturer.
Internal Engine Problems
If you rule out the other causes I’ve mentioned, then this could potentially be the reason why your air filter is soaked with oil, particularly if your mower is quite old. A blown head gasket, damaged cylinder or worn cylinder rings are all potentials causes of oil traveling a path it should not and reaching the air filter.
If this is the case, unless you have considerable knowledge and experience with small engine repair, you’re going to need the help of a specialist to repair and reconstruct the engine. Depending on how much your mower is worth, it may actually be more financially viable to just buy a brand new mower, as engine repair can be expensive.
I Can See A Bit of Oil in My Filter: Should I be Worried?
Paper filters shouldn’t really ever have any oil on them. But if your mower has a foam air filter, you should be aware that a light coating of oil is completely normal. In fact, it’s necessary. It’s actually this oil that prevents dust and dirt from passing right through it.
It’s also fairly common that this type of air filter can get oilier over time, and that’s why you need to periodically remove and clean your filter to restore it to its optimum condition.
All I’m saying here is, don’t freak out if you notice your foam air filter is slightly oily. It’s supposed to be.
Prevent a Lawn Mower Air Filter Soaked in Oil: A Few Final Tips
To wrap this post up, let’s very quickly summarize the main things you can do to prevent a lawn mower air filter from becoming soaked in oil.
- Don’t tip your mower the wrong way (#1 tip by far).
- Don’t put more oil into your mower than is recommended by the manufacturer.
- Be careful when storing your mower and make sure it’s completely level.
Observe these few simple but important rules, and you’re far less likely to experience this problem again.
About Tom Greene
I’ve always had a keen interest in lawn care as long as I can remember. Friends used to call me the “lawn mower guru” (hence the site name), but I’m anything but. I just enjoy cutting my lawn and spending time outdoors. I also love the well-deserved doughnuts and coffee afterward!
Комментарии и мнения владельцев
I tipped my mower the wrong way and gasoline got in my filter. I let it dry out. Is it safe to run it?
Hey Barbara, That’s the worst, I’ve made the same mistake before. To answer your question, it isn’t dangerous to run your mower with the soiled filter, but the best bet is to replace it. Gasoline won’t cause as big of a mess as oil would, but it will still deteriorate the structure of an air filter. For the short term, if the mower starts and runs you shouldn’t run into any problems. However, if the filter was damaged by the gas (which I think is quite likely) it won’t be able to filter air correctly in the long term. Good luck Tom.
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