I finally got my engine alignment tool in and began to work on it last night. I was unable to insert the tool easily into the coupler even after lots of adjustment. I can find where there are grease marks on the top of the tool and the bottom. Adjust it between there and still wont insert. The marks are directly on top and bottom of tool. Nothing side to side. Is there anything else I should look for as far as rear motor mounts being bad, coupler?? (Alpha 1, mercruiser 120)