There's a small crack in my carb body, any body have any ideas on how to fix it?

 

I can't see in your photo where the crack is, but replacement is the best bet. JB Weld may seal a non-load bearing crack.

 

Is it near that vacuum nipple? I would have no problem skim coating some JB weld in the crack there and wiping it off the gasket surface.

 

Its by the vacuum nipple, I put some JB weld on it, seems like it fixed it

 

I can see a very small crack by the vacuum port....

You know, all I would do is get a tube of red "permanent strength" thread locker and put that in the crack. Its alot more fluid than something like JB Weld, so it will seep into the crack and seal it up better. Just put a bead of it over the whole crack, let it sit for a minute, then while its still fairly fluid, use a razor blade like a squeegee to scrape off the excess, sorta like you would use a putty knife. Then leave it for a couple hours to cure. Then it should be all sealed up.