I would do two things-Number one: Don't get in a rush. Take the time to run a test possibly using your old carb or a scrap card from salvage if you can. Secondly: The JB Weld sounds like a good idea, but if there is any question as to how it will hold up when saturated with fuel, make a test "Blob" of JBW and let it soak for a week or even more in your particular fuel combo to see if it degrades at all. I would then make a final decision based upon these results. I know, it ain't quick, but at least you will have the peace of mind that it will stand the test of time (for at least a week or so!).