Help! I Put Gas In The Oil Tank Of My Lawn Mower | How To Fix It Fast?

Your lawnmower, much like your car, needs fuel and oil in order to function correctly. However, in contrast to your car, the gas and oil filling holes on lawn mowers are typically located much closer to one another. Two-stroke engines consume both oil and gas during combustion; four-stroke engines, on the other hand, burn just gas and keep their oil in a separate reservoir.

So, if you put gas in the oil tank of your mower and it has a four-stroke engine, you must take quick action or suffer the consequences. In this article, you will learn the best thing to do if you accidentally put gas in the oil tank.

I accidentally put gas in the oil tank

Accidental fluid mismatches in an engine can cause overheating, fire, and engine destruction.

It is unfortunate that one would make the error of pouring gas into the oil tank, but the situation is not terribly difficult to fix. Even I, too, have been guilty of doing something similar to this on a number of occasions. Therefore, there is no need for panic, and the following are some simple suggestions that can assist you in removing the gas from the oil tank.

These suggestions will require you to empty the oil tank of your lawn mower, which, if not done correctly, is an environmental hazard and adds to the risk of fire. However, if you don’t do this, it could have some fairly devastating effects on the engine of your mower.

Having said that, now that you have gas in a place where it shouldn’t be. So, what are you going to do next? Keep reading to find out!

What Happens If You Put Gas In The Oil Tank?

accidentally put gas in the oil tank

It is recommended to change and replace the oil of your mower for every 50 hours of run time.

The functions of oil and gas are different from one another. To ensure that everything works well, gas and oil must be put in the tanks that are specifically designed for them. However, both oil and gas are necessary for the lawn mower to function correctly. If you fill the oil tank on your lawn mower with gas, the machine will not work. It is not an uncommon problem, and many people do it accidentally and quite often.

Nevertheless, if you try to turn on the lawn mower by putting gas in the oil tank, it will not work. When you put it in while the engine is running, it will cause the engine to stop, which will be the first indication that something is wrong with your lawn mower. 

If the fluids in an engine are not put in their specific compartments, there is a risk of the engine overheating, a fire starting, the engine being destroyed, significant injury, or even death (in rare, worst-case situations).

RELATED: Starting A Lawn Mower That Has Been Sitting For Years | A Complete Guide

How To Rid Of Gas From An Oil Tank?

Lawn mowers often include a toolbox that contains the appropriate tools; yours ought not to be any different. These are the tools that are required to open the tank in order to empty the liquid. In the event that you do not have a kit, you will need the following tools to remove the contaminated fuel from your lawn mower’s tank:

  • Flathead screwdriver
  • Fresh gas
  • Fuel-safe container
  • Pliers
  • Rag or paper towel

Remove The Spark Plug

Remove the spark plug

A spark plug is a mower component that ignites the fuel-and-air mixture.

If you find that there is a problem, you should not even consider starting the mower. Instead, you should look for the lid that is set over the spark plug and detach it so that you can inspect the spark plug. This will allow you to check the spark plug. 

To remove the spark plug from the engine, first loosen it with a spark plug wrench, and then pull it out entirely. This acts as the primary source of protection against shock in the event that the battery is activated.

Follow Fuel Line To Carburetor

accidentally put gas in the oil tank

A fuel line is a hose or pipe that transfers fuel from one point to another.

Next, look for the point at which your gasoline line emerges from the gas tank. When you spot it, you’ll be able to track it all the way down to the carburetor. It will most likely be fastened to the carburetor using a teeny-tiny hose clamp to hold it in place. In the event that there is no fuel line that is easily accessible, you should attempt to remove the fuel from the tank using a siphoning method.

RELATED: How To Fix Lawn Mower Sputtering: Common Reasons & Easy Fixes!

Clean The Oil Drain Plug

Clean the oil drain - accidentally put gas in the oil tank

The oil drain plug is a screw plug that can be built out of either metal or plastic.

When it comes to the plug that removes oil from the engine, you shouldn’t take any chances at all. In order to properly clean the oil drain, which is situated underneath the deck of the mower, use a rag or paper towel. 

It’s possible that the oil drain stores a mix of gas and oil. So, keep this area clean because it is one of the most efficient ways to protect the crankcase of the lawn mower. Make sure there is nothing blocking the drain plug by inspecting it closely. 

The crankcase is susceptible to contamination from gas and oil because of its location. All in all, make sure that the drain plug area has been thoroughly cleaned.

Drain The Tainted Gas

If all goes according to plan, the oil tank should be totally purged of all of the liquid that was previously contained within it. Even if it seems as though any liquid that is left in the oil tank may be oil rather than gasoline, you should still remove all of the fluid because it would have combined with gasoline nonetheless. All in all, it is best to remove all of the liquid from the container before doing anything else.

Make sure to carry out this activity outside, in a location that has adequate air circulation, so that any potentially hazardous gasses can escape, and the interior of the oil tank can totally dry up. After you have completely emptied the oil tank, keep the oil tank cover off the mower overnight so that any gas that may still be present in the oil tank has time to evaporate before you replace the oil in the tank with fresh oil.

Replace Drain Plug

Replace the drain plug when you have finished emptying everything and check to make sure everything is in its proper location. Also, ensure that the cap is positioned correctly, so there are no leaks.

Fill The Oil Tank With Fresh Oil

Next, you will need to change the oil in your lawn mower. However, under no circumstances should you ever put gas or a combination of gas and oil into the oil tank of your lawn mower, even if there is only a small amount of gasoline present. It is possible that this will cause significant damage to the engine of the mower, which will be extremely expensive to repair.

Change The Oil Filter

After something like this occurs, you may or may not be required to replace the mower’s oil filter depending on the type. Having said that, you should take this as an opportunity to change your oil because you’ll need to put new oil in the oil tank anyway, so you might as well change the oil filter simultaneously and provide the new oil.

Start The Engine

It is now safe for you to attempt to start your lawn mower engine once you have removed all of the gasoline from your oil tank, replaced your oil filter, and added fresh oil to your oil tank. However, if your mower does not start, you must consult with an experienced mechanic as soon as possible.

RELATED: How To Locate and Clean The Carburetor On A Lawn Mower? | A Beginners Guide

Final Thoughts

If you have mistakenly put gas in the oil tank of your lawn mower, it is not a death sentence. It is possible to clean the system and get your lawn mower back to work. 

Also, you do not need the assistance of a specialist to complete the task, and it does not demand a significant amount of your time or resources. 

So, using the drain plug, completely drain the oil tank, let the tank air out, and dry thoroughly over the night.  

Before adding new oil, you should completely dry the oil tank. Next, attempt to start the engine. If the mower still functions, you are good to go.

Frequently Asked Questions

What happens if you put the wrong fuel in a lawn mower?

In some cases, putting the incorrect fuel in a gas tank might seriously harm the engine. Putting gasoline into a diesel engine is likely to result in the most trouble. Nevertheless, with any fuel type, issues can be overcome by replacing the fuel.

Can you use regular car oil in a lawn mower?

It is possible to use certain kinds of motor oil in a lawn mower, particularly if it has a four-stroke engine like those that have become more common in recent years. However, a two-stroke lawn mower engine requires special oil.

What happens if you put oil in a lawn mower’s gas tank?

Even if you make the mistake of putting oil in the gas tank instead of gas, the lawn mower will be undamaged as long as you empty the tank and fill it with fresh gas immediately. Move the mower around so that the oil may drain from the gas tank, and make sure that you get as much of it out as you can.

What is the best way to clean a lawn mower’s gas tank?

If you can, take the gas tank off the mower and empty the entire tank of dirty fuel. However, the tank will still contain some oil, so add a tiny amount of clean fuel, stir it around, and dump it as well. This ought to almost completely drain the oil from your tank.

Why does my lawnmower not start?

If the gas in your mower is from the previous season, it might not work. In addition, a spark that is sloppy, unclean, or missing completely might also be another reason why your lawn mower won’t start. So, check it out, clear it of debris, and reconnect it.

Sources for Further Reading

Mowers and mowing safety – University of Minnesota Extension Service

Lawn Mower Care and Safety – University of Florida Extension Service

Lawn Mower Tune-Up – University of Delaware Extension Service

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