That's a 1/8" NPT pipe thread, and it's going to be pretty tight. You probably need to use a straight-flute "E-Z Out" and a little heat to get it to budge. Use a Propane torch, but only after you disassemble the carb and get the float, and the needle valve and seat out of it. If you can wait a while before tackling the project, I've got an inspection job pending in B'ham in the next few days. I'd be glad to help out if you like.

I've used candle wax on stubborn threads at times. Get the casting hot enough to melt a candle or some parrafin, and apply it liberally before trying the EZ out.
Jerry


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