Re: 1960 5.5 fisherman lower unit
My procedure was something like this. Grind at it with a slot screwdriver. Try bending up the inner metal of the seal if you can. Pull on it with pliers. Pry up with a seal puller (a J ended piece of hard metal). Take a break... Pull, whack, grind, heave. .. Take another break. All this while ensuring that no damage gets to the outer piece holding it in there.
This goes on for a while, then the profanity starts. The seal starts to budge a little at this point. Oh yeah, some heat doesn't hurt ... but not sure if it helps either. A few more pulls, whacks, grinds, heaves accompanied by more discustingly dirty profanity and presto ... out she goes.
Piece of cake !