What Fuel Do Racing Go-Karts Use?

Karts are unique machines with two-stroke engines that are completely different to what you would find on your average road car. One of the most important things an engine needs is fuel, and so you may be wondering what fuel racing go-karts use.

Racing go-karts use 91 or 93 octane pump gas combined with 2-stroke engine oil. The oil and fuel mixture differs depending on the type of engine. For example, Rotax karts need about 25 milliliters of oil for every 1 liter of gas, or a ratio of 40:1. Mixing fuel with oil keeps the engine lubricated.

Racing karts can use different types of fuel depending on the type of engine that they have. However, in the majority of cases, karts use petrol mixed with 2-stroke engine oil. It’s important to understand how fuel affects a go-kart’s performance and reliability, and I’ll explain why below.

Several go-kart drivers racing on a wet track with barriers on either side of the racing surface, all of them are equipped with wet tires, What Fuel Do Racing Go-Karts Use?

Do Go-Karts Use Petrol?

The majority of go-karts use petrol in their engines. Petrol is used in karting engines because it is less dense than diesel, which means that it ignites faster and leads to better performance. Ultimately, when racing karts, performance is what drivers are after, so using petrol makes much more sense.

However, you can’t just use pure petrol in your 2-stroke kart (most racing karts are 2-strokes). In karting, the petrol needs to be mixed with 2-stroke oil. This is because kart engines don’t have their own oil reservoir, so to keep the engine lubricated and running smoothly, you need to mix the oil with the petrol before putting it into your fuel tank.

It can be tricky knowing how much fuel your kart needs, but it all depends on the engine that you have. Each engine has its own specific requirements in terms of the oil and fuel mixture, and it’s important to check the specific measurements needed for your engine. Below are the measurements for the three most popular karting engines: Rotax, IAME, and ROK.

2-Stroke Go-Kart Oil/Fuel Mixtures

EngineOilFuel/Oil Ratio
IAME X30Castor25:1
ROK MiniCastor30:1

How Oil Affects Fuel

It’s important to get your fuel and oil mixtures right because it will affect the performance and reliability of your kart’s engine. The oil is used to lubricate the engine and protect it from damage and excessive wear, so you need to make sure that you’re using enough oil in your fuel mixture.

If you don’t have enough oil in your fuel, you’re going to be damaging the engine and causing it to wear out faster. This can ultimately cause the engine to seize, which will require you to rebuild the entire engine or buy a new one (at a high cost).

The downside to using oil in the fuel is that it makes the fuel thicker. When the fuel is thicker it can’t combust as easily. The fuel becomes denser, which will affect the performance of the engine. So, you want to hit the sweet spot for your oil and fuel mixture, but it’s not always easy.

According to Rotax, you should use a 3% oil mixture when breaking the engine in (or about a 30:1 ratio of fuel to oil). This is because the engine is still new and needs a lot more lubrication. Once the engine has some miles on the clock, you can drop the oil mixture down to 2% to improve the engine’s performance (closer to 50:1).


• Go-karts use petrol with an octane number of about 91-93

• Most racing karts are 2-strokes, so you need to mix oil with your fuel

• The specific ratio of this fuel and oil mixture will depend on the specific engine your kart uses

Does Octane Number Matter In Go-Kart Racing?

The octane number of the fuel in your racing kart doesn’t matter a great deal as long as it’s within a rough range of about 91-93. Some engines may be tuned to run on higher octane fuels, but you should always make sure your engine will handle it before you change which fuel you use.

NOTE: Unless you have a custom kart engine or one that specifically requires higher octane numbers, there is no need to use high octane racing fuel in your kart

Ultimately, if the engine is not built and designed to use high octane fuel, you most likely won’t get any benefit from using it. If anything, it could cause your engine more harm than good. If you’re unsure about the octane number needed for your engine, check your manufacturer’s manual.

How To Know What Go-Kart Fuel To Use

The best way to know what fuel your go-kart needs is to look up your specific engine. For example, if you have a Rotax engine, you can visit their website or find a manual for the engine online. This allows you to get the most accurate and reliable information for your specific engine.

I highly recommend you consult the engine manufacturer rather than someone else about the fuel and oil you should be using in your kart’s engine. You never know where someone else got their information from, and they might be just as confused as you are when it comes to the oil and fuel mixtures in the engine.

It’s not something that you want to get wrong because the consequences can be catastrophic. If you can’t find any details about the engine manufacturer online, you could always try to get in touch with the manufacturer directly through email or via phone call. If all else fails, your second point of contact should be a retailer that stocks that engine.

Fuel In Racing

In addition to finding the right type of fuel for your kart, you also need to make sure to check the legality of your fuel in the championship you aim to race in. Just like with the chassis and engine manufacturers, scrutineering will be strict with the type of fuel you put into your kart’s engine.

Because the type of fuel that you use can affect the performance of the kart, it’s important for the event organizers to control this element. It could give a driver an unfair advantage if they turned up with high octane racing fuel compared to someone who is using 87 octane petrol in their kart’s engine.

The advantage might be minimal, and it often doesn’t seem to make a difference. But it’s important to keep everything as equal as possible in a karting championship. Make sure you check what type of fuel your local championship runs, and always use the same type of fuel even if you’re just doing testing. Otherwise your testing runs won’t be consistent with your kart’s performance during quali and the race.

Do Diesel Racing Karts Exist?

When it comes do racing, diesel karts aren’t really a thing. That’s because diesel is not the ideal fuel for kart racing as it’s denser and typically has lower maximum RPM ranges than petrol. This means that diesel lasts longer, but it usually doesn’t offer as fast acceleration as petrol.

There are some custom-built diesel powered karts, but as far as mainstream racing karts go, you won’t find any diesel powered engines. It’s highly unlikely that diesel kart engines will become popular in the future too. Electric karts are potentially the future, and they may become the go-to in racing series in the future.

Final Thoughts

Go-karts use 91 or 93 octane petrol, just like the petrol you would fill your car with at a gas station. However, you do need to mix 2-stroke oil with your fuel to make sure that the engine is lubricated. 2-stroke racing karts do not have engine oil reservoirs, so they need to have a mixture of oil and fuel running through the system.