New member and new to ATV world

Hi all, I’m new to the world of ATV’S and excited to learn a bit about them as well! Recently purchased an old quad, 84 TRX 200. When I looked at it was running and not leaking anything. Until, I drove it onto the truck and it started leaking gas. Got it home and it fired up for a short time and stalled out and the leak continued. Turned the petcock off to stop the leak. The leak is coming from the overflow valve on the carburetor. I’m sure this a common problem? Any advice where I can start to get this problem solved? Thanks for reading! Cheers!!