I managed to repair the cast aluminum part the lever screws onto.  I used a super glue to repair the cracks, then cut a piece of aluminum flat bar and filed it to shape to fit on top, epoxied it to reinforce my repair.  Then I re-attached the repaired part to the post using Gorilla Glue.  It works now, but looks a little rough with the black epoxy bar glued on top of it.  I plan to paint it all with silver enamel to make it all look like one solid piece again.

It works to advance the line space and carriage, but the spring that returns the lever is not working and probably not attached.  Has anyone repaired this?  If I take the left carriage knob off, will I be able to access the spring and reattach it?

Thank you.  Yes, that might help.