The off-road karts, regardless of they’re two or four-stroke engines, will utilize a form of petrol. It’s not the situation if the go-kart is powered by an electric motor. Kart engines most usually run on unleaded petrol.
In the United States, you normally have octane ratings of eighty-seven (regular), eighty-eight to ninety (middle-grade), and ninety-one to ninety-four (premium). In general, as long as it is unleaded, it ought to be suitable. If unsure, always refer to the owner’s manual, where it’s frequently mentioned.