Re: Crack at bottom of outboard motor, Can it be welded?
James Propeller in Carrollton, Tx. (at used to be) does all sorts of prop repairs. Years ago he expanded his business to include just what your requested. Yes you can weld it (a little post op required....possible gasket/seal replacement, new lower unit fluid....no biggie).
Find a prop shop that does it and go for it.
Mark