How to drain gas from your lawn mower

How To Drain Gas From A Lawn Mower

So, we have almost reached the end of another mowing season and you’re starting to think about packing away your lawn care tools. You probably won’t be needing that gas lawn mower again for another few months but we wouldn’t recommend just throwing it into the shed and forgetting about it.

Quite the opposite. Just as you need to perform maintenance on your mower during the months it is in use, you’ll need to keep it well maintained while it’s in storage. One of the worst things you can do is to leave gas in the mower when it’s out of use. If you are storing your lawn mower for more than 30 days, you’ll need to know how to empty gas from a lawn mower.

Not doing so will cause potential corrosion within the tank which can then result in problems with the engine and the mower getting started. There are a few ways you can drain lawn mower gas and this guide tells you everything you need to know.

Understanding that leaving gasoline in your lawn mower isn’t a good thing has probably given you a nudge to remove any that is left over in the tank at the end of mowing season. Of course, if you’ve never done it before, you’re probably wondering how to drain gas from a lawn mower. The good news is that there are several ways of doing this which will be outlined in the steps below.

Prepare The Engine

Before you do anything else, it is essential that you use a fuel stabilizer. This substance is designed to extend the life of fuel when it is in the tank. It contains additives which stop the gas from breaking down and leaving behind a sticky deposit which can wreak havoc with the engine and other internal parts. If you’re leaving fuel in the tank for an extended period, it would always be recommended to add a fuel stabilizer.

But it also works well when it comes to draining the engine as any residual gas will be treated and won’t cause any harm to your machine. Just pop in the recommended amount and allow the engine to run for a few minutes which will give the stabilizer time to move through the system.

Remove The Spark Plug

Bad Spark Plug

When you perform any sort of maintenance on your lawn mower, it is vital that you remove the spark plug and draining the gas is no exception. If you don’t, then there is a risk that the engine will fire up accidentally which could result in a nasty accident. Just imagine what could happen if a spark plug accidentally created a spark while you had gas flowing freely.

It takes moments to remove the spark plug and could be something that helps to avoid catastrophe.

Choose Your Method

When it comes to how to drain lawn mower gas, you have a few choices in how you’ll approach the task. Some are safer and easier than others so we would always recommend opting for these where possible. In any case, you will be using similar equipment. Let’s take a look at what options you have.

Method One: Siphon Pump

For the safest, quickest and most efficient way to drain gas from your lawn mower, you will need to use a siphon pump. You can get manual pumps or automatic ones which are operated using a simple switch but both work in the same way and will deliver the same results.

These pumps have a central tube and clear tubing. The pump is designed to create suction to get the fuel to start flowing and when this happens, you’ll only need to rely on gravity to finish the job. Pretty simple, right?

You will notice that the tube on your pump is different at either end and that’s because each end is designed for a specific job. It’s important to identify which end is which so that you don’t put the tube in the wrong way. Note that the end that you need to insert into the tank will be made from brass. Simply put this into the fuel tank and make sure it goes right into the liquid inside.

As you squeeze the pump, the suction is created and the gas will begin to flow.

using Siphon pump

Method Two: Increasing The Internal Air Pressure

Again, with this method, you will need to use a clear piece of tube or hose and you’ll need to cut this into two pieces; one longer than the other.

You’ll start by taking the longer hose and putting this into the container that you’ll be using to collect the fuel while the other end goes into the fuel tank. When you put it into the tank, you must ensure that it is fully submerged.

With the smaller piece of tubing, you’ll still put this into the tank but so that it sits just above the fuel. Now take a wet rag which you’ll use to seal the gap between the two pieces of tubing; this will prevent air from getting out of the tank. You can now blow air through the smaller hose using either your own breath or an air compressor.

As you do this, the air pressure inside the tank goes up which will in turn make the fuel flow down the bigger hose and out into the container on the ground. As with the previous method, once this starts happening, you don’t need to do much else as gravity will pull the remaining fuel out.

Method Three: Using Your Mouth (Not Recommended)

If you absolutely cannot perform any of the methods we have already discussed then it may be possible to use your mouth. However, this is not something that we would ever recommend as a day to day method and really should be reserved for an emergency.

Much like the other methods, you are going to need some clear hose. Use a longer piece and put this into the gas tank ensuring that, just like before, you completely submerge the tube. You’ll put the other end of the hose into your mouth; you can see where this is going and why we wouldn’t recommend it, right?

This time, it will be your mouth that creates the suction within the tank to get the fuel flowing. As you do this, it’s essential to watch the tube as this will allow you to see when the gas starts coming up. The last thing you want is to end up with a mouthful of fuel; this will not taste good and more importantly, it’ll do you some real harm.

In order to avoid this even more effectively, just have your hand wrapped around the hose so that you can quickly pinch it while you remove your mouth. You can then direct the tube into your container, let go and allow gravity to do the rest.

Clean Any Debris In The Tank

When you have drained all of the gas out of the fuel tank, this is a brilliant opportunity to perform a little extra mower maintenance before you put it away for the winter. Make sure to start by cleaning up any fuel spills and then you can check for debris.

The air filter is one part that may become clogged so be sure to inspect that. In some cases, you may be able to clean it but there’s also a chance that it’ll need to be replaced. Don’t put off doing this as without a clear air filter, your engine won’t run smoothly.

Also take the time to check the oil filter to make sure that this is not clogged with dirt or debris. If it is, then again, it may be necessary to change it.

When you’re ready to use the lawn mower again, make sure to add fresh fuel into a clean tank and everything should run as you would expect.

Why Do You Need To Drain Gas From A Lawn Mower?

why fdo you need to drain gas from lawn mower

Over the summer, many homeowners take great pride in maintaining their lawns but as we approach the colder months, the grass won’t grow and there’s no need to mow any more. This signals the end of mowing season and time to store your equipment until spring rolls around.

But a lot of people make the mistake of just putting the mower into the shed and leaving gas in the tank. Let us tell you that this is never a good idea. Yes, it’ll save you time now but when it comes to using the lawn mower again, you’ll find that you have problems starting it up.

While there may be other causes of engine issues with a lawn mower, fuel left in the tank is one of the most common causes. In the fuel, there are compounds that, when not burned, will evaporate. For starters, this takes away from how combustible the fuel is so it won’t be as effective. Secondly, the evaporated compounds result in a gummy, sticky residue all around the fuel system which can clog the filter, fuel lines and even your carburetor. At best, you’ll have problems getting the mower going in spring and at worst, it’ll refuse to fire up at all.

When this happens, you may end up having to replace parts which can get expensive. Not to mention the extra work you’ll have to put in before you can even think about mowing. If you want the best out of your equipment, you need to be making sure that you take good care of it.

Even if you are storing your lawn mower for a shorter period of time; perhaps when you go on a long vacation during summer, you’ll still need to drain the fuel. This is because problems can arise within as little as thirty days.

How Often Do I Need To Drain The Gas From My Lawn Mower?

If you are going to store your lawn mower for any longer than 30 days then we would recommend draining the fuel tank. If you don’t, then some of the issues we have discussed in this guide could become a very real problem for you.

However, it is also possible to add a fuel stabilizer to the tank if you’re not storing it for months at a time and this will extend the life of the fuel.

Draining Gas Without A Siphon

Can you imagine coming to drain your lawn mower only to realize that you don’t have a siphon? Does that mean that you cannot drain the fuel? Not at all; there are a few options on how to drain gas from a lawn mower if you don’t have a siphon.

First of all you could just run the mower engine until all of the fuel is used up. This requires very little effort from you but could take some time to get the tank completely empty. When you do this, it is a good idea to use fuel stabilizer as there may be a small amount of gas left over and this will help to avoid problems while in storage.

There are some lawn mowers whose fuel line is directly connected to the carburetor which means it is a lot easier to access. In this case, you should be able to drain the fuel without a siphon.

draining gas without siphon

Take a container and then disconnect the fuel line. Any fuel in the tank will simply flow through and can be directed into your container. Make sure that you replace the fuel line once you have emptied the tank and take the time to check the filters to ensure they are clean and ready for use next time you fire up the mower.

What happens if you come to use your lawn mower but it just won’t start up? Apart from being pretty annoying, this doesn’t have to be the end of the world. But if you don’t have a clear tube or a siphon pump then there is another way; using a turkey baster!

Yes it might sound odd but this common kitchen tool can come in super handy in this situation. Just put the end of the turkey baster into the tank and squeeze the bulb to create suction. Once the turkey baster is full, squirt the liquid out and go back in. We realize that this will take a considerable amount of time, especially with a full tank but when you have no other option, it is effective.

Final Thoughts

At the end of mowing season, you might be tempted to put your machine straight into storage without removing any of the fuel in the tank. While this probably feels like the easiest option, you’ll only end up creating more work for yourself down the line.

Leaving fuel in the tank for extended periods can cause mayhem to the internal parts of your lawn mower and will clog up the fuel system as the fuel evaporates. It’s really not worth damaging your machine when you could take a few minutes to drain the fuel before storing the mower.

There are a few ways of doing this; some easier and quicker than others. But whichever method you choose, your future self will thank you when it’s a lot easier to fire up the mower come spring.

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Andrew Fisher

Andrew Fisher

Andrew is a dedicated father of three who really takes pride in his lawn and garden. You'll find Andrew behind the scenes of almost everything Edge Your Lawn produces. When he's not helping readers find all the information they need, he's in his backyard working on his lawn and garden landscaping. This year he hopes to build an outdoor deck and sort out his veg patches.

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