I'm with Nick. I think it's highly unlikely it's actually coming from the case. It's most likely that's the path the fuel is traveling from the carb.
Check all fuel lines, float bowl seal, float bowl pin.
I'd take the carb off turn on the gas and see if and where it's leaking from on carb. Start there and I think you'll find your problem. At the least you can then eliminate the carb as a source of the problem.