Abstract: A valve stroke adjustment locking mechanism comprising a valve seat having an axially extending bore therethrough and a seating surface. A valve operator is provided having an elongated member which is extended through the axial bore and is reciprocatable between a first open position and a second closed position. The elongated member includes a threaded end portion which extends from the valve seat for accommodating a valve assembly which is provided with a top portion forming a sealing face and a bottom portion having a central opening adapted to receive the threaded end portion of the elongated member. A closed end nut threadingly engages the threaded end portion of the elongated member and contacts the valve assembly for positioning the sealing surface a predetermined spacing from the seating surface.