How to Clean Your Metal Lawn Mower Gas Tank in 9 Easy Steps


Did you just try to start your lawn mower after a long winter, and nothing happened? If so, don’t panic yet! The solution could be as easy as cleaning out your metal lawn mower gas tank. How exactly are you supposed to clean your metal lawn mower gas tank? 

To clean a metal lawn mower gas tank, start by taking the appropriate safety precautions. After the working environment is safe, drain the tank, clean the tank and the carburetor, and then replace the tank. It also is important to check for rust. 

Do you want to know more about cleaning a metal lawn mower gas tank? If so, keep reading to learn the steps to clean your gas tank, why cleaning your gas tank is important, preventative maintenance tips, and how to remove rust from your gas tank. 

how to clean metal gas tank

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Don’t have an old metal gas tank, but need to get tips to clean a plastic resin fuel tank? Read our article, “How to Clean Your Plastic Resin Fuel Tank”.

Items needed to clean out your lawn mower gas tank: face maskOpens in a new tab., safety glassesOpens in a new tab., fuel containerOpens in a new tab., flash lightOpens in a new tab., fuel additiveOpens in a new tab.

Steps to Clean a Metal Lawn Mower Gas Tank

If your metal lawn mower gas tank is full of debris, rust, or old gasoline, it might not start running. This is a common problem when you attempt to start the lawn mower after a long period of inactivity. If you are experiencing this issue, cleaning your lawn mower gas tank may fix the problem. 

There are several steps to properly cleaning your lawn mower with a metal gas tank. It is important to do all of the steps to keep you safe and ensure that your gas tank is clean. There also are several different parts that you may want to replace on your lawn mower to keep it running efficiently. 

Are you ready to clean your lawn mower gas tank? Up next, we’ll outline nine easy steps for you to clean your lawn mower’s gas tank. 

Work in a Safe Environment 

One of the most important steps to cleaning your lawn mower gas tank is taking the proper safety precautions. Here are some of the dangers associated with cleaning your fuel tank:

  • Dangerous fumes
  • Fire hazard
  • Hazardous chemicals

Before you maintain your lawn mower or clean the gas tank, it is essential that you read the lawn mowers operating manual. The manual will have additional safety precautions and instructions on how to maintain the lawn mower. If you need help or have additional questions, reach out to the manufacturer of your lawn mower before you get started. 

Because gasoline and gasoline fumes are flammable, be sure to avoid smoking near the gas tank and keep it away from any flames or heat sources. When you take the gas out of the tank, store it in a safe place. 

When cleaning the gas tank, you will be working in an area with gas fumes. The area should be well-ventilated to minimize the fumes that you breathe in. You also should wear a face maskOpens in a new tab. to prevent breathing in the fumes. 

In addition to wearing a face mask, you should wear safety glassesOpens in a new tab.. You may be using harsh chemicals to clean your gas tank and remove rust, and you don’t want those chemicals to get into your eyes. Chemicals can cause pain and long-term damage to your eyes. 

When using harsh chemicals, it is a good idea to keep a water hose nearby. If you accidentally spill any of the chemicals, you should dilute them by using water. 

Check the Spark Plug

Now that you are aware of the safety precautions you need to take, it is time to clean your metal gas tank! The first step to cleaning your lawn mower gas tank is to check your spark plug and remove it. 

What Does the Spark Plug Do?

A spark plug is an essential part of your lawn mower that allows it to run. A spark plug ignites the gasoline and air combination to create combustion inside the engine. The engine combustion is what allows your lawn mower to start and continue running. 

A spark plug consists of a center electrode and a firing electrode. When a spark plug becomes dirty, old, or corroded, it may not work as well as it should. This can lead to engine misfire, poor engine performance, and increased fuel usage. 

How to Inspect a Spark Plug

Because you are removing the spark plug to clean your gas tank, you should go ahead and inspect the spark plug to ensure it is working as it should. If it is not, your lawn mower will continue not working, even if you clean the gas tank. 

Here are some things you should check for when examining your spark plug:

  • Broken electrode
  • Carbon buildup
  • Corrosion

If your spark plug visually appears to be in good shape, the next step will be to do an ignition test. To do an ignition test, you will need an ignition tester. This will allow you to see if your spark plug produces a spark that can start the lawn mower engine. If there is no spark, you will need to replace the lawn mower’s spark plug for it to work again. 

Replacing a Spark Plug

Did you know that you should get a new spark plug for your lawn mower every year? Getting a new spark plug each year is a great way to maintain your lawn mower and ensure that it lasts for a long time. 

If your spark plug isn’t performing as it should, you need to replace it. This will greatly improve the performance of your lawn mower. Spark plugs are affordable, easy to replace, and can improve the performance of your lawn mower.

Removing the Spark Plug

Even if your lawn mower’s spark plug is in good shape and does not need to be replaced, you still need to remove it before cleaning your lawn mower’s gas tank. If you do not remove the spark plug, you risk the engine turning on while you are cleaning your lawn mower. 

Even with the gas tank removed, there could still be gas fumes inside the lawn mower that can allow the engine to start. This is dangerous and a situation that you want to avoid. In addition to removing the spark plug, you also should disconnect the lawn mower’s battery. 

Drain the Gas Tank

Once you have removed the spark plug, it is time to drain the gas tank. To drain the lawn mower’s gas tank, you will need to have a gas canisterOpens in a new tab. to ensure that you are safely storing the gas. 

Make sure the gas canister is directly below the gas tank and detach the fuel line. Be sure to clamp the fuel line to the carburetor before you get started. Once you have done that, the gas will drain into the fuel canister. 

Make sure that all of the gasoline has drained before you stop. Once all of the fuel is in the canister, use a flashlightOpens in a new tab. to look at the fuel tank. Here are some questions to ask yourself while looking at your metal gas tank:

  • Are there cracks in the gas tank?
  • Are there holes in the gas tank?
  • Is the gas tank full of debris?
  • Is the gas tank rusted?

If you answered yes to any of the above questions, these are issues that will need to be fixed. While you may be able to repair your gas tank, in extreme cases, your gas tank will need replacing. 

Clean the Carburetor

The next step to cleaning your lawn mower’s metal tank is to clean the carburetor. A carburetor is the part of a lawn mower that creates the ideal air and gasoline combination for combustion within the lawn mower’s engine. 

If the carburetor is dirty or clogged, your lawn mower’s engine will not perform as well as it should. You may notice reduced engine power or a gurgling noise if your carburetor is bad. 

Here are the steps that you need to take to clean your carburetor:

Remove Outer Castings and the Air Filter

To clean your carburetor, start off by removing the outer castings on your lawn mower. All you need to do is remove some screws and taking the castings off. Once you have done that, remove the air filter to get to the carburetor. 

Remove the Carburetor

Like the outer castings, the carburetor is held in place by bolts or screws. To remove the carburetor from the fuel line, you will need to undo the screws. Some fuel may leak from the carburetor or the fuel line when you detach the two. Be prepared to clean up the leaked fuel with an old rag. 

If you don’t see fuel when you remove the carburetor, that is a sign that you have a problem. The fuel line may be blocked, not allowing fuel to flow through. If that is the case, you may need to replace the fuel line and figure out what is causing the blockage. 

Clean the Bowl and the Nut

Once you have removed the carburetor, the next thing you need to do is clean the bowl and the nut. You can clean the bowl by using a carburetor cleaner. After you clean the bowl, you can remove it by unscrewing the nut. 

When you remove the nut, you must check to make sure that nothing has gotten into the hole of the nut. This is one of the main causes of a carburetor not working as it should. 

To check for debris, you can insert a small pin in the nut to remove any buildup. Once you have made sure there isn’t any debris in the hole, clean the nut using the carburetor cleaner. 

While the nut and bowl are taken apart, you should check for damages. Here are some signs to watch out for:

  • A bowl that is so dirty that it cannot be cleaned
  • Clogged nut
  • Cracks in the bowl
  • Holes in the bowl

If you notice any of these damages, you may need to replace the carburetor bowl, nut, or both. 

Replace the Carburetor Needles

The next thing you need to do when cleaning your carburetor is to replace the needles. You will find one of the needles inside the bowl, holding the float to the bowl. The other needle is located on a small gasket inside the carburetor. You should replace both of these pins.

Clean the Carburetor

Now that you have cleaned the bowl, nut and replaced the needles, it is time to clean the carburetor. Use the carburetor cleaner to clean the carburetor and all of the holes. 

Like with the nut, use a pin to clean inside the carburetor holes. If any of the holes are clogged, the carburetor may not work. 

Replace the Main Gasket

Unfortunately, the main gasket inside the carburetor only performs for a certain amount of time. If you are putting in the effort to clean the carburetor, it could be a good time to go ahead and replace the main gasket since you have taken the lawn mower apart. All you have to do is take out the old one and insert a new one. 

Reassemble the Carburetor

Congratulations! You have cleaned the carburetor. All you have to do now is put everything back together. One of the best ways to remember where all of the pieces go is by taking pictures with your phone as you take apart the carburetor. This will give you a visual reference to remember where everything goes. 

Rinse the Gas Tank

Once you have cleaned the carburetor, the next step is to clean the inside of the gas tank. If there is rust inside the tank, you will need to use a special cleaner to clean it out (more on this later). 

To clean the inside of your gas tank without the presence of rust, all you need to do is rinse it out. Do not rinse your gas tank with water! Water can create issues for the carburetor, spark plug, and engine. 

Instead of using water, you should use a small amount of fresh gasoline. If you use the gas that came from the inside of the fuel tank, you could be rinsing with gas that has debris and dirt in it. Be sure to use new gas. 

Because this gas will likely have debris in it after using it to clean the inside of the tank, you should dispose of it instead of using it. Having debris in your gasoline can clog an engine. Take the used gas to a hazardous waste site near you to dispose of it the right way. 

Clean Your Metal Tank

Clean Your Metal Fuel Tank with Acetone Cleaner

In addition to rinsing out the gas tank, you should clean the inside of the tank with a cleaner if you have a metal tank. With metal gas tanks, debris is more likely to stick to the side of the tank. It requires more effort to get the debris and dirt off the side of the tank. If you don’t, your tank won’t be clean, and you could eventually have a problem with rust. 

The best cleaner to use in a metal tank is one that contains acetone. Acetone cleaner will help get rid of any buildup in the tank, and the acetone will evaporate quickly. This will prevent the cleaner from sticking around in your gas tank, causing condensation. 

To clean with an acetone cleaner, add some of the cleaners to your gas tank, and then shake the tank. Pour out the cleaner in a container that you can easily dispose of. Be careful handling cleaners that have acetone in them. Remember to read the instructions and always work in a well-ventilated area. 

Clean You Metal Fuel Tank with Small Rocks

Another method I suggest is kind of an old school way of cleaning your tank. This is the method I use. Remove the fuel tank and make sure it is empty of fuel.

Add a few handfuls of small rocks or pebbles to the inside of the fuel tank and add a little bit of solvent. I use kerosene or diesel fuel, but water even works. Shake the fuel tank from side-to-side or up-and-down.

If there is any rust inside the fuel tank, the rocks will knock the rust loose. Rinse the tank and the the rust will come out of the tank. Complete the procedure a couple of times until rust no longer rinses out of the fuel tank.

Examine the Fuel Filter & Fuel Lines

The last thing you need to check before putting the fuel tank back together is the fuel filter. The fuel filter’s job is to collect any debris, dirt, or impurities before they go into the fuel injector. Dirty fuel can cause unnecessary wear and tear on your lawn mower and cause the engine to have poor performance. 

Similar to many other lawn mower parts, the fuel filter should be replaced every year. This is the perfect time to replace the fuel filter because the rest of the gas tank will also be clean. 

Check the fuel lines to make sure thee are no cracks and the lines are not dry rotted. If they are, you need to replace them. Most fuel lines are made of 1/4 inch or 5/16 inch rubber fuel hose.

Look at your fuel line clamps. I recommend changing the type of clamps you use to a worm gear clampOpens in a new tab. if you happen to be currently using pinch style clamps. This will help minimize fuel leaks due to using an inferior style clamp.

Put the Tank Back Together

Now that everything is all clean, you need to put it all back together. Before putting everything back together, be sure to replace all of the parts that needed to be replaced. Here are the parts you should consider replacing:

  • Carburetor bowl
  • Carburetor main gasket
  • Carburetor needles
  • Carburetor nut
  • Fuel filter
  • Gas tank
  • Spark plug

It is easier to go ahead and replace these parts while the lawn mower is torn apart. Replacing the parts will allow your lawn mower to run better. Don’t forget to reconnect the spark plug and connect the lawn mower battery. 

Fill up the Gas Tank

Lastly, all you have to do is fill up the gas tank! Since you cleaned out your entire gas tank, you should use new fuel in the tank. Putting the old fuel in the tank will add more dirt and debris. Also, the old fuel could have been part of the reason why your lawn mower wasn’t starting in the first place. 

Once you have filled up the gas tank with new fuel, try to start the lawn mower. It should start up with no problem. If your lawn mower still isn’t starting, it is a sign that there is another issue. 

Read more about gas and the best type of fuel to use in your lawn mower in “This is the Type of Gas Lawn Mowers Use“.

Importance of Cleaning a Lawn Mower Gas Tank

Because fuel is necessary to run the lawn mower’s engine, it is essential to keep your lawn mower’s fuel tank clean and in good condition. When your lawn mower sits for an extended period of time, there could be a buildup of dirt, debris, and condensation inside the fuel tank. 

Here is what can happen if you don’t clean your lawn mower’s gas tank:

  • Engine misfire
  • Poor engine performance
  • Reduced fuel efficiency

When to Clean a Lawn Mower Gas Tank

If you use your lawn mower regularly, you won’t need to take it apart and clean it often. The only time a lawn mower fuel tank needs cleaning is when it has sat for an extended amount of time. 

Here are some signs that your gas tank needs cleaning:

  • The lawn mower has sat for a few months without use
  • The engine is not performing as it should
  • The gasoline is more than three months old
  • There is debris in the tank

While you won’t need to clean your lawn mower gas tank often, you should still change the internal parts as needed. This includes the fuel filter, spark plug, carburetor nut, and the main gasket. 

Lawn Mower Gas Tank Maintenance

If you want to prevent cleaning your lawn mower’s metal gas tank in the future, there are some maintenance steps you can take to keep your gas tank in great shape. After all, cleaning the gas tank is a time-consuming activity that you won’t want to do often. 

Here are some tips to prevent needing to clean your lawn mower’s gas tank:

Keep reading to learn more about these preventative maintenance tips!

Use Fresh Fuel

One of the first maintenance tips is to always keep fresh fuel in your lawn mower. Even if you don’t mow the grass often, be sure to change the fuel at least every three months. Doing so will ensure that debris and condensation do not build up in the gas tank. 

After you change the fuel, remember to dispose of it properly. Don’t attempt to use it in another tool or vehicle. 

Add a Fuel Stabilizer 

If you don’t want to clean your gas tank after every winter, consider adding a fuel stabilizer. A fuel stabilizer will prevent your fuel from going bad quickly. Not only will adding a fuel stabilizer save you time, but it also can save you money if you don’t plan on using your lawn mower often. 

I like a product called Sea Foam. This will stabilize fuel for two years. Sea Foam will help with residue and deposits left in your fuel system. It will also reduce moisture build up.

Find out more about Sea FoamOpens in a new tab. and why I like it in our article, “Why Use Sea Foam Fuel Additive in a Lawn Mower“.

Clean and Repair the Lawn Mower Carburetor

Keeping your lawn mower’s carburetor in good shape can go a long way. If you clean the carburetor every so often, you can increase the lifespan of your lawn mower, allow it to work more efficiently, and decrease the odds of needing to clean the entire gas tank. 

Remember to repair carburetor parts as needed and replace the internal parts once per year. You can even purchase a carburetor repair kit to help you get the job done. 

How Do You Get Rust Out of a lawn Mower Gas Tank?

If you have a metal gas tank that has rusted, don’t worry. There are still things you can do to get rid of the rust inside your gas tank. After you clean your gas tank with acetone cleaner, fill the gas tank with vinegar and leave the tank to sit overnight. 

The vinegar will allow the rust to dissolve and become soft overnight. In the morning, you can finish cleaning out the gas tank and remove the rust. Be sure to give your gas tank plenty of time to dry out before attempting to use it again. 

In addition to using abrasives to get rid of oil in a gas tank, you also can use abrasives. Here are some examples of abrasives that can help eliminate rust:

  • Aquarium gravel 
  • BBs
  • Gravel
  • Loose bolts

If the rust has created holes or cracks in the metal gas tank, you will need to get a new gas tank. Be sure to check your tank for any signs of corrosion. 

How to Prevent Rust in a Lawn Mower Gas Tank

While it is possible to clean rust out of your metal gas tank, it is easier to prevent rust from happening. Rust can permanently damage your gas tank and should be avoided if possible. 

Here are some of the consequences of having a rusted metal gas tank inside your lawn mower:

  • Fuel line blockage
  • Irregular fuel injection
  • Rust inside the engine

To prevent rust from forming in your lawn mower’s gas tank, start by creating a mixture of baking soda and water. Put the mixture inside your metal gas tank and swirl it around. Dispose of the mixture properly, and then flush the tank with soapy water. 

After you get rid of the water, put a small amount of diesel fuel in the tank. The diesel will coat the outside of the tank and create a light oil. This oil will help prevent rust from forming on the tank and will not cause any issues with the gasoline inside the tank. 

Are You Ready to Clean Your Metal Gas Tank?

If your lawn mower has been sitting for a while and it is not starting, it could be time to clean your lawn mower’s metal gas tank. If you need to clean the gas tank, be sure to take the appropriate safety precautions, read your owner’s manual, and follow the steps above. After you clean the gas tank, your lawn mower should be running like it’s brand new!

Powered Equipment Team

We're just a guy and a girl obsessed with outdoor power equipment! We are excited to share the knowledge and tips we have learned over our combined 55 years in the power equipment industry. We have both ran equipment dealerships and took pleasure in helping our customers everyday providing equipment repair, parts, purchasing, and business tips to our residential and commercial clients. We hope our blog will help you with your next purchase, repair, or project.

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