While most tracks do not have a weight limit, you will be able to perform much better if the vehicle is lighter. Therefore, the heavier you are, the slower you will accelerate. If you weigh less than your fellow racers, then you have a competitive advantage over them.
Weight is also directly related to size, and if you are particularly heavy, you are probably also bigger. This can play havoc with some karts as not all have adjustable seats. Some also feature pretty constricting sidebars, which can make it harder for a bigger racer to get into the go kart.
Many large racers can still take part, though. Due to the strong steel alloy which is used to create the chassis of a go kart and can support a large amount of weight. Therefore, weight isn’t really as much of an issue as the size. If you are a bigger person who wishes to delve into the world of go kart racing, then it’s best to make sure that the track you plan to visit has adjustable seats.
Many popular tracks also list the dimensions of the karts on their website, or may be able to tell you over the phone. This allows you to double check whether you will be able to fit into the kart comfortably.
If it comes down to it, you can always buy your own go kart. If you buy your own, you’ll be able to find a go kart that you can fit in perfectly, allowing you to be comfortable. An increasing number of tracks will let you use your own go kart too.