I don't think they are actually bolts, they are studs I think. You have to take the nuts off and then the carb can be wiggled around so you can get the linkage off then it just slides up and off.
But if you really want the studs out for some reason then screw 2 nuts on one stud and tighten them so they lock together then you can unscrew the stud by using the locked nuts. Make sense?