Drain Gas From A Lawn Mower

How To Drain Gas From A Lawn Mower? [Step-By-Step]

7 minutes

If you already have a lawnmower, you will no doubt be familiar with gasoline, as it is the component that feeds the engine. But, did you know that if you keep the gasoline inside the engine for extended periods of time, it can damage the engine of your mower?

So, it’s necessary to learn how to drain gas from a lawn mower, if you are going to pack away the engine for the whole winter season. 

Let’s get started!

How To Drain Gas From Lawn Mower: Step By Step Guide

In this article, we will outline the best and easiest methods of draining the gas from your lawn mower with the hopes that you find the optimal solution for your situation. 

Firstly, let’s have a look at why it is important to drain the gas from the lawn mower. 

Why Drain The Gas From Your Lawn Mower?

Gasoline is one type of flammable liquid that burns by releasing volatile compounds that dissipate over time. This reduces the combustibility of the fuel. 

Furthermore, as the components dissipate, they leave sticky residue throughout the entire fuel system of the engine.

The residue settles at the bottom of the engine’s fuel tank, which lowers the condition of the gas even further. The outdated fuel goes throughout the engine when it starts, and then clogs the fuel filter, fuel line, as well as the carburetor.

Your mower may become unusable as a result of this.

How To Drain Gas From Your Lawn Mower

As we have already discussed the negative impacts of keeping the gas on the mower’s engine for a long period of time, you might now be convinced to drain the gas from your lawn mower. 

So, let’s find out how to drain the gas from the lawn mower.

There are two methods for this. One is done using a siphon, and the other is done without a siphon. We will discuss both of them. 

Method 1: How to drain the gas by using a siphon 

Using a siphon is an easy and simple way to empty a tank of liquid. This tool is ideal for the equipment that has fuel lines and which are very difficult to access. 

A siphon is a tube that will suction the gas upwards from where you need to drain it, the liquid will then subsequently flow downwards outside of the engine’s storage and drain the fuel. The liquid will continue to flow through the tube, usually by immersion or suction. 

Required tools and materials

  • Siphon 
  • Fuel stabilizer 

Step 1: Make the engine ready

A fuel stabilizer helps the fuel of the engine last longer by preventing it from dissolving into a sticky residue. 

Insert the gas stabilizer and run the engine for a few minutes before draining the tank. The stabilizer will be circulated via the fuel filter, fuel line, fuel tank, and carburetor. 

The fuel-stabilizer treated gas that remains in those areas of the entire fuel system will be ignitable and will now keep the engine safe.

Step 2: Cool down the engine

Allow the engine to cool down after the fuel has been cycled through it.

Step 3: Keep the mower on a flat surface

No matter if you have a riding mower or push mower, be sure that you’re working on a level surface. Fuel from the fuel tank can leak out if the mower is not on a flat surface. 

Step 4: Pull the spark plug

Remove the spark plug by lightly pulling on it. It is necessary to remove the spark plug to prevent any accidents. This will stop the engine from starting accidentally. 

This also prevents the spark plug from accidentally sparking while a flammable fluid is running outside the tank. 

Step 5: Empty the tank

A siphon pump is a most convenient as well as safest and fastest way to drain the gas from the tank. Some of the siphon pumps are automated, which only requires flipping a switch. There are also other types that can be operated manually, however, they all work in the same way. 

The siphon pump has a clear tube along with a pump in the middle. The pump creates the initial pressure that allows the liquid to flow. Once the liquid starts to flow consistently through the tube, gravity will finish the rest of the job.

A siphon pump’s tubing has two separate ends that perform different purposes. For this reason, ensure that the hose is not inserted backward. The brass end of the hose always goes inside the tank.

Dip the hose’s brass end into the fuel. After that, Squeeze the siphon pump several times to start the suction. Then the fuel will flow by itself. 

Step 6: Cleaning 

After removing the hose, clean the gas spills by using a clean cloth. Make sure to clean the air filter by removing any residual dirt.

Next, put some gasoline inside the gas tank and shake the tank slowly, which will remove any debris left on the surface of the tank. After that, drain out the fuel. 

Give the tank some time to completely dry out. Or, you may use an air compressor to dry out the inside of the tank properly.

Step 7: Connect the spark plug

After you have done with the cleaning, connect the spark plug. Your lawn mower is ready to rest. 

Drain Gas From A Lawn Mower

Method 2: How to drain the gas without a siphon 

Required tools and materials

  • Drain container/ drain pan
  • Drain tube/ plastic tube/ hose 

Step 1: Park the lawn mower 

Set the lawn mower on a level, sturdy surface. You may use the parking brakes to keep the lawn mower stable. Then disconnect the spark plug as a safety precaution to avoid any accidents. 

Step 2: Set up the plastic tubes 

You will need two transparent plastic tubes to drain the gas from the tank. One piece of the plastic tube will need to be long enough to connect the gas tank with the container. 

Put the drain container on the flat surface, just near the mower’s gas tank. The container will have to be lower than the bottom of the lawn mower’s gas tank. 

Now, put the long tube inside the gas tank in a way that the tube remains totally submerged into the fuel of the gas tank and reaches the bottom of the tank. 

Put the other side of the long tube into the drain container. 

After that, put the short tube by the side of the long tube and enter a few inches of it into the tank. However, the short tube should not reach the fuel of the gas tank. It will create an air passage between both the fuel tank and the surrounding environment.

Then use a wet cloth to seal the cap of the mower’s gas tank through which the tubes entered the gas tank. 

Step 3: Drain the gas 

Now it’s time to drain the fuel from the gas tank. 

To do that blow into the open side of the short tube, or you can use an air compressor to make the task easier. 

After repeatedly blowing into the tube, the fuel will start to come out through the long tube. You will be able to see the fuel through the transparent tube. 

Once the fuel starts to come out, you won’t need to blow, as the pressure difference and gravity will complete the task. 

Make sure to take time and drain the tank properly. 

Step 4: Remove the tubes

Once you see that the fuel stopped coming out of the tank, you can remove the tubes and seal the fuel tank. 

Step 5: Run the mower

This technique might not be able to drain 100% of the fuel. A small amount of fuel might still remain. To remove this fuel, start the engine of your mower for a few minutes and let the mower run out of fuel. This is an important step to take as a safety precaution.

Signs of fuel that has gone bad

If you have difficulty starting the engine of your mower, the engine stalls, roughly idles, or produces a pinging noise, these are all indications that fuel has damaged your mower’s engine. 

Other signs to look for are that the fuel will smell bad or different from usual, and it will have a darker color. 

Safety precautions

  • If you are going to follow the second method and will blow into the tube, be cautious that you don’t inhale the fuel, the fuel should never go into your mouth. 
  • Always remove the spark plug as mentioned previously.
  • The process should be done outdoors and in a properly ventilated area. 
  • When working with gas, always eliminate any sources that can cause a spark or ignition.
  • Never run the mower inside your garage. 


Hopefully, you have found this article on ‘how to drain gas from lawn mower’ informative and easy to follow. Always check to make sure you aren’t packing away your mower with the fuel inside throughout the winter season. 

Finally, don’t forget to follow the instructions provided by the manufacturer to make the process easier. And, of course, don’t forget to take the necessary safety measures before jumping into the process.

Best of luck!

Todd L Miles
Lawn Mowers Enthusiast
I started "Landscape and Lawns Care" to provide clients with lawn care with better service, better products and, most importantly, better ethics. My promise to every customer is to give the greenest grass possible while controlling weeds, insects, and diseases! The most important thing is that I strive to always do the right thing for you, your lawn and your wallet!