An actuator for a plug valve of the type having a body with a central chamber having diametrically opposed inlet and outlet ports and a plug within the chamber having a transverse passage therethrough and an upstanding stem.PLUG VALVES The plug has a first, upper, valve-open position with its transverse passage in alignment with the inlet and outlet ports of the chamber, and a second, Globe Valveslower valve-closed position wherein its transverse passage is oriented at 90