The first company in America to produce go karts was the Go Kart Manufacturing Company in 1958. In 1959, McCulloch two stroke engines where used for the Go Karts being produced. As time progressed, motorcycle engines were adapted to be used on go karts and today there are some really fast high performing go karts being used in the kart racing circuit.
Most indoor kart arena use electric powered go karts some of which can be pretty fast. They are low maintenance and do not emit any emissions which is important in a closed area for obvious reasons.
Outdoor tracks rarely use electric and most use either 2 stroke or 4 stroke motors. If it’s an amusement park style track, then the motors have been throttled not to exceed a certain speed so sometimes you can get a fast or slow car. They are still pretty fun to ride.
If it’s a real racing style track, then the cars have no speed limit other than what the motor is capable of producing and some of the motors are modified motorcycle engines so they are capable of producing some really fast speeds.
So, when your buying a used go kart, be sure you buy them for what they were designed to do and for the purpose it’s going to be used for. Of course, buying them where you can bid on your willing to pay will make it easier to stay in your budget.