This is the result of a missing O ring. I know
the history of this motor since new. After 50
some years of regular use a lower unit seal
was leaking. Found this when disassembling
for repair. Most likely the O ring dried out
and disintegrate decades earlier. If your reading
this, and you have any of these, and you have
never checked for this O ring, you should.
Tubs.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.