The animations and demos on this page cover much of the basics that you need to understand if you're going to have to set up a kart for racing. For those who are serious about racing, you will need to visit one of the karting forums to get more current and more detailed information. For those who aren't sure what a modern kart is like, visit the Margay web site. If you think are interested in racing and being competitive, expect to spend hundreds of hours reading and learning about cart setup. It's VERY involved. Expect to spend at least $1500 on your first kart. That will be for a used kart that's only a couple of years old. New karts from top manufacturers can easily cost $3500+. That doesn't include the engine. You'll also have to buy tires that are best suited for the various tracks. If you don't have a trailer, you'll likely have to buy one if you get serious about racing. It's difficult to get everything in the back of a pick-up and it's a pain to have to load and unload everything for every race.
Basic Engine Repair:
There are two pages on this site that will help you to get an engine running if it has carburetor problems. THIS is the first one you need to read because it has some general information that's not included on the other page. It covers 4-stroke engine carburetors. THIS one covers 2-stroke carburetors (like those used on string trimmers and chainsaws). Bear in mind that they are not yet complete but they contain good information if you're new to small engine repair.
The animations and demos on this page cover much of the basics that you need to understand if you're going to have to set up a kart for racing. For those who are serious about racing, you will need to visit one of the karting forums to get more current and more detailed information. For those who aren't sure what a modern kart is like, visit the 
Basic Engine Repair: