[pdxmotorhead]

Go to a GOOD marine shop that works on boat outdrives.
They are used to this kind of repair. A good tig welder will
be able to weld it right up with little problem.

Now,,, Remember, welds can crack, he's pulling a hail mary for you.
If it doesn't work You now get to change the oil pan. It may not
crack for a LONG LONG time, it make crack 5 minutes later (Not likely).

Are you sure its a crack? They didn't just forget the copper washer on the drain plug? Or accidentaly re-use the old one?

Dave