Re: 1967 mercury 500 lower unit
First never pry, it is too easy to crack that case. You have 2 nuts not yet removed. There is a nut on the front top side, I guess you have it off, two on either side in the middle that cannot be removed fully until the lower unit drops partially, two on the bottom side just forward of the prop, and one hidden bolt underneath the aluminum trim tab. Keep the one front topside on a few turns and remove the two on the sides as far as you can, remove the hidden bolt, and loosen the two on the bottom side. You should see the lower unit start to drop. An extra set of hands or a floor jack help at this point. If not lightly rap , don't get carried away, the casing with a rubber mallet along the edge. If you only get a small seperation and the lower uniot still hangs up use a piece of thin tapered wood, like one for shiming a door, to coax the lower unit apart. I picked up a motor that spent its whole life with the lower unit submerged in water while attached to a boat at the owners private lake and I had to use several shims to get the lower unit to drop. Have patience and you will prevail.
