1992 Buick Roadmaster fuel cutoff switch

Car has run perfectly always. Drove up to parking place running great, went into house and back out 15 min. Later tried to start and just turned over and over, replaced ignition module, nothing still. Replaced coil, still nothing, cap & rotor, still nothing so I squirted starting fluid into carb and started imediately. Question is could it be fuel cutoff switch? I think I bumped the bumper of the buick while parking my other car. If so where is the cutoff switch on 1992 buick roadmaster?
thanks Mel