I cannot seem to get the larger diameter retaining pin/screw through the rear port. Light tapping with a hammer got it about half way through and then it refused to budge. Tapping it back out the other end with a punch was a chore as well. Is my Marine Finish on mine too thick or something? The instruction videos I have all seen were all either drop in or took 2-3 very light taps to seat where needed. Any advice would be greatly appreciated.