I polished the spring and frizzen lug to a mirror finish, lubed it with some Mobile 1 grease, assembled and worked it about twenty times, so far it is functioning as you would expect it should. While I was working on it I remembered something Jim Chambers said here on this forum about twenty years ago, to the effect that, the vast majority of problems we find with returned locks is the lack of proper lubrication. This is not one of his locks but I have always followed that advice, well, til now I guess.
Thank you fellows, very much appreciated.
Robby