Re: 1967 lower unit oil/water mixture leaking after using
If you have possibility to pressuretest (tools) by your self, do that.
There are eight seals( if I count right) in that house.
Drainscrewseal, ventscrewseal, driveshaftseal (under the waterimpellerhousing), shiftshaftseal, propshaftseal, pivopinseal (do not touch screw at gearcase), bearringcageseal (o-ring) and one seal (o-ring) under a plainwasher for one pinbolt for connecting to the middleg.
All this seals are cheap and common seals. You find them at hardware machineshops or at FranzeMarine.
Total cost not more then 30 dollars ( I think)