If you are really getting into this antique outboard hobby, It would pay to invest in some special tools. For pulling seals I use an inturnal three jawed slide hammer (check out Harbor Freight) to remove seals. It pulls evenly and has less danger of distorting the housing. An impact screw driver is invaluable for removing stubborn screws. You hit it with a hammer so the force keeps it in the slot while twisting. A torque wrench and strap wrench are needed for installing Flywheels. (as well as a Flywheel puller. to take them off.) One of our members, Frank Robb, builds duplicates of some of the factory tools that are as good as or better than the factory originals at a very reasonable price. Before Frank’s tools, we would run a tap into the shift rod seal retainer (after removing the shift rod – 8^D) and then used a threaded rod to remove the retainer. Some used a long wire with a hook on the end to pull the "O" ring and a small size long screw driver to push in a new one. THis could scratch the retainer and leave the new "O" ring in worse shape than the old one.