what fuel should I use in my lawn mower

What Type Of Gas Do Lawn Mowers Use?

If you want your lawn mower to perform to the best of its ability then you’ll need to make sure that you take good care of it. Part of that is choosing the best gas for lawn mowers as using the wrong type can hinder your mower’s performance. So, what is the best gas for your lawn mower?

Regardless of whether you have a 2 cycle or 4 cycle engine, you’ll need to use a regular unleaded gas. The octane rating should be no less than 87 and the gas should contain no more than 10% ethanol. That said, it is possible to use premium gas but the octane rating will need to be higher, typically between 91 and 93. If you are using a 2 cycle engine then you can mix either of these gas types with your engine oil.

Understanding exactly what type of gas for lawn mowers works best will ensure smooth running of your machine and a longer service life. This guide tells you everything you need to know.

Choosing the right gas for your lawn mower is crucial but which you go for will largely depend on the type of engine your mower is fitted with.

If you have a 4 cycle engine then, for the most part, you’ll need to use fresh unleaded fuel that has an octane rating of no less than 87. It’s also a good idea to choose gas whose ethanol content does not exceed 10%…more on this later!

For those of you that are using a 2 cycle engine, you’ll again need to use fresh unleaded fuel and make sure that the octane rating is no lower than 87. The difference here is that you’ll also need to use a good quality engine oil. Because of this, your 2 stroke engine will take either premium or regular gas.

As long as your mower fuel is less than 10% ethanol, has an octane rating higher than 87 and is clean and fresh, you shouldn’t experience any problems.

filling lawn mower with gas

What Types Of Gas To Avoid For Your Lawn Mower

When putting gas in lawn mowers, you want to make sure that you don’t add anything that’s going to adversely affect your machine. A lot of people will head to their local gas station to purchase fuel for their lawn mowers and that seems like the most convenient way, right?

While it is convenient, you have to keep in mind that your local gas station will probably be selling fuel with a much higher ethanol content than is recommended for a mower. Typically speaking, this can be up to 85%. Putting this in a small engine like the one on your mower isn’t a great idea.

You should also make sure to never use diesel in your lawn mower. This might feel as though we’re teaching you to suck eggs since you’ve got a gasoline engine so why would you use diesel. But the sad truth is that one too many mower owners have made this mistake.

Using diesel in a small engine like this can open up a whole world of problems. It’s easily done by mistake if you aren’t paying attention when pumping gas so always be sure to double check.

Ethanol-Blended vs Ethanol-Free Gas

As we have mentioned, if you buy your gas from the local filling station, this will have a much higher ethanol content that you’d want for your lawn mower. Most of the time, this will be around 15% but it can be far higher, up to 85%. These are ethanol blended fuels.

Ethanol comes from grain and it’s used in fuel as it is more eco friendly than other options. But the problem is that, when ethanol is left standing, it adversely reacts with the materials that are used to make your lawn mower engine such as metal and plastic. This can cause damage.

On the other hand, there are ethanol free fuels which do not contain this chemical that comes from grain. That said, you won’t be able to get these at your regular gas station as they’re only sold at places like hardware stores and service centers.

Premium vs Regular Gas

A lot of people wonder do lawn mowers take regular gas? The answer to this question is relatively complex since most mowers will run perfectly well on both regular and premium fuel.

Reading this guide will point you in the right direction when it comes to choosing the best gas for your lawn mower. However, your first port of call should always be your owner’s manual as this will provide you with the most relevant information for your tool. If you ignore the advice in the manual, this could lead to your warranty being voided if the fuel you use causes damage to the mower.

You’ll then want to consider the compression ratio of the lawn mower. When you are using a mower with a higher compression ratio, you’ll need to use a much higher octane fuel. This typically means going for a premium gas and will ensure the best performance. That said, pretty much all mowers will run on regular gas so you won’t have any issues if you do choose to use it.

It can make life easier if you understand the octane rating system. Premium fuel with a high octane rating has fewer fillers added to it which essentially means it is much purer. But as we have mentioned, your mower will run perfectly well on regular fuel so premium isn’t absolutely necessary, especially when you consider the higher cost.

Some people note that premium gas does not have as many additives but that doesn’t affect how much you’ll need to use. Ultimately, the cost will be higher and you won’t be getting any extra for your money.

It’s also worth pointing out that the time of year will determine the best gas for your lawn mower in terms of premium vs regular gas. If you’re mowing in the summer then you’ll find that regular gas is better whereas for winter mowing, we’d always recommend going for premium.

Tips To Keep Your Lawn Mower Healthy

As well as choosing the right fuel for your lawn mower, there are some other things you can do to make sure that it runs smoothly. Here are our top tips on keeping your lawn mower healthy.

1. Use Fuel Stabilizer

This is something we have mentioned in previous posts but it’s of the utmost importance; storing your mower with fuel in the tank for long periods of time can affect the internal components. If you’re going to store the mower fuel for any longer than 30 days, you must use a fuel stabilizer.

This is because, after this length of time, the fuel will begin to break down. That said, ethanol free products tend to have a longer shelf life. However, by adding a fuel stabilizer such as Seafoam or Stabil, you won’t experience problems as quickly.

That’s because these products act as a sort of antioxidant. They’ll take moisture out of the fuel, preventing the degradation of the chemicals which can lead to deposits building up on the inside of the tank and fuel lines.

When using a fuel stabilizer, be sure to follow the instructions carefully and only use the recommended amount. Another great reason to use this is that, when pulling the mower cord, you’ll notice less resistance and stalling.

2. Empty Fuel Tank During Winter

As we have discussed, leaving fuel in your tank for long periods of time is not good. It is for this reason that you should completely drain the fuel tank before storing your mower over the winter.

If you don’t, then moisture in the fuel will cause corrosion of the internal components. One of the main problems to come from this is damage to the carburettor.

3. Avoid Mixing Gas With Engine Oil

Unless it is recommended by the lawn mower manufacturer, you should not mix engine oil into your gas. We would also advise against making any modifications to a 4 cycle small engine that allow it to run on other types of fuel. Doing this could cause damage to the combustion system and this won’t be covered by your warranty.

Final Verdict: Best Gas For Lawn Mowers

If you want to make sure that you’re using the right gas for your lawn mower then always follow the manufacturer’s instructions. Generally speaking, mowers will take regular gas with an octane rating about 87 and an ethanol content below 10%. Using anything with a higher ethanol content will cause damage to the fuel system. However, if you’re using premium gas then the octane rating should be at least 91 or 93.

Some manufacturers recommend that you use premium gas. Doing this will ensure you get the best performance out of your lawn mower. While the mower will run on regular gas, this may cause premature damage to the engine which will limit the lifespan of the mower’s engine. That said, where the manufacturer’s guide calls for regular gas, you must ensure you adhere to this.

Some manufacturers won’t give you much guidance on the best gas for lawn mowers. If you’re in any doubt, stick with these rules:

  • Always use fresh gas as this will prevent build up inside the engine.
  • Don’t use anything with an octane rating lower than 87.
  • Always use gas with an ethanol content lower than 10%
  • Opt for canned gas where possible as this contains a blend of ethanol free gas and fuel stabilizer. 
  • Go for lower octane fuel in the summer and higher octane fuel in the winter.

Summary

If you have been wondering what is the best gas for lawn mowers then this guide will help you. For almost all lawn mowers, regular gas with an octane rating of 87 or more will be suitable. However, it’s essential to make sure that the ethanol content does not exceed 10% as this could cause damage to your engine.

Some mowers will also run on premium gas but you’ll need to find one whose octane rating is either 91 or 93. Again, the ethanol content should be kept below 10%.

As well as choosing the right fuel, it’s also essential to take good care of your mower engine if you want it to perform well for many years. This includes removing fuel when the mower is in storage and adding fuel stabilizers. All of these things combined will deliver the very best performance and very few problems.

Further Reading

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.