QUICK help broken carb!!!

I had the unfortunate chance to see a broken idle mixture screw casting on a 88cc carb Is the fella out of luck of will J/B weld hold it? It broke right a the base of the carb at an angle. Not sure what to tell him just I would post it here. Have no idea what a factory HD carb would cost. He's hoping it would not be as much as the 42,44 or 25 but ya never know with HD. never used jb weld before but had it reccomended, itwill "hold up" to 600 degrees(figure) it it holds and the bike ends up 600 degrees he may have other problems . any ever tried this or used it?
all it does is hold the idle lix screw and it might have needed adjusted when he put the screaming eagle kit in. Actually I heard it running he went with a 48 slow and a 195 main and sounded good for about 30 seconds while choked. then black smoke and when he got to looking later on he noticed there was a crack in the casting of the idle mixture screw area. so what to do??? Anyone knowing about this would be appreciated for their input. hopefully it'll work and we can go ridiong this weekend.