I bought a 1967 johnson seahorse model RDS 23. I had water in the lower unit. I read how to check what was leaking by submerging the lower unit and using a bike pump. The only air I saw was commig out at the top of the propler. The problem is i don't believe the lower unit on the motor is the origional. How do I go about finding out what lower unit it is to get the correct seal? Can I replace just that seal or should they all be done. Is this something I can do myself? I do most of my own work on my cars but have no experience with outboards. Thanks for your help.
