My 1992 Yamaha 90 has what appears to be a small electric motor cover next to one of the upper rams. When looking at the boat from the rear, it is on the left hand side of the main engine bracket next to the ram. Is this a cover for the motor that makes the trim and tilt work? If so, as it is starting to rust around the base near the mounting screws is this something I should replace before it gets too much worse? Thanks.