1966 mercury 95 horse lower end - spanner nut

[Lieutenant dan]

I found that my gear housing was cracked and that the spanner nut no longer screws into the housing. I was wondering if anyone out there has a lower end gear case for this motor? It is a krakhuaer (sp?) motor. It runs like a champ, so I was thinking of jsut having a guy weld the spanner nut in place since i cannot thread it in. Any other ideas? thank you!