What Type of Gas Is Best for ATVs? Does It Matter?

By asking this question, you are already ahead of the game. Some people won’t put too much thought into what kind of gas they put in their ATVs. They use whatever they have at hand or what is cheapest. 

The best type of gas for an ATV is the one recommended by the manufacturer in the owner’s manual, typically a minimum of 87-octane (regular) or 91-octane (mid-grade) gasoline by the (R+M)/2  method with an ethanol content not greater than 10 percent.

Did you know using the wrong type can cause damage to the engine and that using a higher-grade premium gas is like throwing money out of the window?

What Are the Different Gasoline Types?

At the gas station, you’ll notice by the stickers on the pump that there are several types of gas to choose from. The selection varies from station to station, but most of the time, there are at least three types.

Gasoline is graded or categorized depending on the octane rating or ethanol content. 

The most common grades used at gas stations in the United States, Canada, and Mexico are

Regular: 85 to 87 octane and usually up to 10% ethanol

The term “Regular” is typically used for the lowest octane rating offered at the gas station.

Mid-Grade: 88 to 90 octane and usually up to 10% ethanol

Other standard terms for mid-grade gas are “Plus,” “Extra,” or “Special.”

Premium: 91 to 93 octane and usually up to 10% ethanol

Other standard terms for premium gas are “Super” or “Supreme.” Some stations offer gas with an octane rating of 94 or 95. These types are commonly referred to as Supreme Premium or similar terms.

E85 Flex-fuel: About 110 octane, 15% regular gas, and 85% ethanol

The Ethanol in E-85 raises the octane rating to about 110, causing the fuel to burn cleaner. Only vehicles certified as flex-fuel capable should use this type. Running your ATV or UTV on E85 can be harmful to the engine. 

E10: 87 Octane, 90% regular gas, and 10% ethanol.

This type of gas is usually okay to use on ATVs.

E15: 88 Octane, 85% regular gas, and 15% ethanol.

This fuel type is usually not recommended or even prohibited for use with ATVs. 

What qualifies as regular, mid-grade, or premium varies between states or nations. While one state may accept fuel with an octane rating of only 90 as a premium, another may require a minimum of 92.

Note that the octane rating shown on the pump is not universal. More on this later in the post. 

What Gas Is Best for Your ATV?

The best gasoline for your ATV is the one recommended or required by the manufacturer in the owner’s manual. 

By using the type of fuel the manufacturer vouches for, you can be confident that the ATV will perform as expected over time. 

Here are the manufacturer fuel recommendations for a few popular ATV models to give you an idea of typical gas types. Refer to your owner’s manual to ensure you use the correct fuel type.

For instance, if your owner’s manual says to use gasoline with a minimum pump octane number of 87, you should not use a lower octane fuel. 

• Using gas with a lower octane level than what’s recommended by the manufacturer can reduce engine performance and may cause engine damage over time.

Note that there is no need to panic if you unintentionally fill your tank with a lower grade than recommended. A slip-up won’t cause any damage, but make sure to fill the right type next time. 

• Using gasoline with an octane rating higher than what’s required will not damage the engine but will also not give you any significant performance gains. 

If the manual advises against using fuel with more than 10 percent ethanol content, it’s crucial to steer clear of fuels such as E15 and E85 to prevent potential problems.

Sometimes, the manual includes two types of gas: one minimum octane number and one recommended octane number higher than the minimum. Most of the time, your best option is to choose the minimum alternative. 

In addition to the octane rating and ethanol content, you must ensure the gas you use isn’t too old and has not gone bad.

Also, be aware that gasoline is mixed differently depending on the season. More on that later in this post. 

What Is Octane Rating?

Without getting too technical, we need to know what octane rating is to understand how it affects engine performance.

The octane rating or octane number measures the fuel’s stability. In other words, it measures the fuel’s ability to withstand compression in an internal combustion engine without detonating. A higher number indicates a more stable fuel.

You may have noticed that the octane rating on the pumps in most European countries is typically much higher than in the United States, Canada, and Mexico. But that doesn’t mean European gas is more stable. European octane ratings are typically higher because the rating parameters are different.

To determine the fuel’s octane number, they run two tests known as RON and MON tests, where the fuel is run through a test engine using two different testing protocols.

The MON test typically gives an octane number of 8 to 12 octane, lower than that of the RON test protocol. 

• In most European countries, Australia, Pakistan, and New Zealand, the octane number shown on the pumps is only the RON number.

• In the United States, Canada, and Mexico, the octane number shown on the pumps is an average of the RON and the MON number, also known as the AKI (Anti-Knock Index). This is why it’s written (R+M)/2 with small letters behind the octane number on the pumps.

Why Do the Fuels Octane Rating Matter?

The process that makes an engine run is known as the combustion process. The carburetor sends a mix of fuel and air into the cylinder head, where the spark plug ignites the mixture.

For an engine to work correctly, the fuel must detonate at the right place and time.

• The right place for the detonation is the spark plug’s tip.
• The right time is when the piston is in an optimal position to transform as much power as possible from each combustion into engine movement.

Under some conditions, the fuel/air mix can ignite before it reaches the spark plug, throwing the engine off its timing. This phenomenon is known as pre-ignition or engine “knocking” and “pinging.”

Less stable fuel (lower octane number) has a lower resistance against pre-ignition, while more stable fuel (higher octane number) is more likely to ignite only at the right time and place. 

That is why the first thing to try if you’re having issues with engine knocking is to ensure you use the correct octane rating of gasoline.

Modern fuel-injected ATVs with an engine knock sensor automatically adjust the engine timing and ignition. This adjustment helps reduce pre-ignition, thereby protecting the engine from damage.

However, that doesn’t mean you should run on a lower octane fuel to save money. Running with a lower octane fuel will increase fuel consumption, reduce engine performance, and may lead to engine damage over time.

Should You Use Premium Gas in Your ATV?

When it comes to octane rating, higher is not always better.

Using a higher octane rating than the one advised by the manufacturer is usually not harmful to the engine. Still, it doesn’t lead to noticeable benefits like increased engine power or better mileage. 

Theoretically, you can get slightly more power out of an engine running high-octane gas because you can fine-tune the timing to ignite the fuel earlier. 

A study on car engines showed an average performance gain of 2.7%. While there are no similar tests on ATVs, the key takeaways are much the same. The slight potential increase in power does not justify the 20 to 25% increase in price that comes with choosing a premium fuel.

So unless your owner’s manual doesn’t explicitly say to use premium, it’s usually best to stick with what’s recommended.

In some instances, the user manual differentiates between required and recommended fuel.

Choosing the higher octane alternative may increase performance slightly in situations where you need it the most, like heavy towing or racing. 

However, you won’t notice a difference in everyday riding applications, so choosing the more expensive alternative is not worthwhile from a cost/benefit perspective. 

Premium fuel is only worthwhile with high-performance, high-compression engines, such as on many UTVs, that need high-octane fuel to run correctly.

Suppose the ATV owner’s manual operates with a minimum number but recommends a higher octane fuel. In that case, you should test with the higher octane alternative to eliminate any signs of engine knock. 

What Types of Gas Contain Ethanol?

Ethanol is an alcohol that’s added to gasoline to reduce air pollution. More than 90% of all gasoline sold in the US contains various levels of ethanol. 

On some types of fuel, the ethanol content is indicated by the fuel grading, such as E-10, which contains 10% ethanol and 90% gasoline, or E-85, which has 85% ethanol and only 15% gasoline or other hydrocarbons. 

However, it’s not just E-graded gasoline that includes ethanol; standard fuel types can also contain ethanol. Look for a sticker on the pump that should indicate the maximum allowed ethanol content in the various gas types offered.

Why Does the Ethanol Content in Gas Matter?

As long as you don’t use gas with a higher ethanol content than recommended by your owner’s manual (typically 10%) and use all the gas in the tank within three months, you should not expect any issues related to ethanol in gas.

However, the issues begin when the gas sits in the tank for extended periods. 

Phase Separation

The main issue with ethanol is what’s known as “Phase Separation.”

When the fuel is fresh, the ethanol is evenly dissolved in the gas in a uniform mixture. But ethanol binds more willingly to water than it does to gasoline. 

Over time, the ethanol begins to bind with water from condensation and humidity in the air. And as you may know, water doesn’t mix well with oil (and gasoline). The ethanol-water mix then separates from the gas and sinks to the bottom of the tank. 

When phase separation happens, it reduces the gas octane number, potentially causing engine knocking. The water may cause corrosion in the gas tank and the carburetor. And if the ethanol-water mix enters the combustion chamber, the engine will run rough, if it runs at all. 

The only way to fix phase separation is to completely drain the fuel tank, fuel lines, and carburetor and add fresh, new fuel. 

While Phase separation may lead to some potentially severe consequences, it’s relatively easy to avoid:

• Make sure you use the gas before it gets three months old.
• Add fuel stabilizer to the gas or drain the gas tank before you put the ATV away for winter storage.
• Keep the gas tank full to prevent condensation. 

Ethanol Can Cause Corrosion

Ethanol may cause corrosion, but not for the reasons you may think.

While ethanol is corrosive to rubber gaskets, connectors, and fittings, studies have shown that it is no more corrosive than pure gasoline.

However, the ethanol-water content in fuel that has phase separated will cause metal components to corrode.

Fuel Containing Ethanol Does Not Go Bad Quicker

Some believe ethanol causes fuel to go bad quicker or is what causes the ATV to gum up, but that is not the case.

Gas goes bad because some of the components evaporate. This process happens over time if the gas sits for more extended periods. 

The remaining components react with oxygen, causing a gel-like substance that clogs filters, fuel lines, and the carburetor. 

This process happens to any gas type regardless of factors such as ethanol content or octane number. 

Should You Use Non-Ethanol Gas in an ATV?

Gasoline containing no ethanol is becoming increasingly hard to come by and is more common in premium grades.

Using non-ethanol fuel in your ATV is safe and might result in slightly improved mileage. However, any potential savings in fuel consumption are often offset by the higher cost of non-ethanol fuel.

Note that some UTVs require ethanol-free fuel to run correctly and to start at colder temperatures. 

Summer vs. Winter Gasoline Blends

The recipe used by the oil companies when making gas is not the same in the summer as in the winter. 

Summer fuel is designed not to evaporate as quickly in warmer weather to prevent vapor lock issues.

Winter gas, however, is designed to evaporate faster to aid in cold weather starting.

For optimal performance throughout the year, it’s recommended to drain any remaining fuel each spring and fall. Add fresh fuel from a high-volume gas station to ensure the fuel you get is season-appropriate.

Leaded vs. Unleaded Gasoline

ATVs run on laded and un-leaded gas, but leaded is no longer available.

Back in the day, gasoline used to contain lead additives to help prevent engine knocking by providing a cushioning effect in the engine. 

However, studies conducted in the sixties indicated that lead fuel caused health and environmental problems. This study and a long political process eventually led to leaded gas being banned worldwide.

Two-Stroke ATVs Require Oil-Mixed Gasoline

Both two-stroke and four-stroke ATVs generally use the same type of gasoline. However, two-stroke engines require that the gas be mixed with two-stroke oil in the proper ratio.

Two-stroke engines are not designed with an oil reservoir (oil pan), so oil must be added directly to the fuel to lube moving components.

The typical oil mix ratio is 2-4% but always refer to your owner’s manual, as using the wrong blend can harm the engine.

Related Questions

What Kind of Gas Does a 110CC ATV Take?

Most four-stroke 110cc ATVs use regular grade 87 gas. Note that some 110cc ATVs are two-stroke, which requires gas mixed with two-stroke oil for proper engine lubrication.

What Is the Best Gas for a Chinese ATV?

Most four-stroke Chinese ATVs use regular grade 87 gas or higher. Note that some Chinese ATVs are two-stroke, which requires gas mixed with two-stroke oil for proper engine lubrication. 

Do ATVs use Regular Gas?

Most ATVs use regular gas, while some high-performance engines need higher-grade premium gas to run correctly. Two-stroke ATVs need gas mixed with two-stroke oil for proper lubrication.