I have a 1987 Cobra sterndrive T0481586 / 984541 4.3 . On the port side of the upper drive, almost in the middle, is a recessed area with a screw. Most of the diagrams show the starboard view ( Seloc manual). Can any one tell me what that screw threads into? What it held in place? I cannot get it threaded back in, there is just nothing there. Thank you in advance.