Cool kart! ~ It's got one of the IAME brand engines made for racing in the TAG kart classes.
Your problem might just be caused by too high of an Idle speed. But If not, you'll find lots of online info, videos and parts to adjust, repair or replace your old clutch.
IAME has made serveral different engine models that look fairly similar to yours, but you should be able to positively Identify yours by comparing your engine to the pictures, carburetor part numbers & engine part numbers to the various models you'll find listed at this site: -->
Tech Forms – IAME KARTING