Yeah, I had leaking from my #2 carb, rebuilt the whole thing, put it back together and... still leaked. Check for small holes/cracks in the overflow tube. And to be safe you can always double check them with a compressor to make sure they're air tight. And if you find a hole/crack you can pretty easily fix them with epoxy/jb weld type stuff. Just make sure they are built to withstand gas, and let them cure long enough