This is an original exhaust rocker arm lever for a small Nelson Brothers hit and miss gas engine.  It has been extensively repaired as can be seen but it might be better than your broken or missing one.  It is from a 1 1/2 or 2hp engine.  This was on a running engine when removed from service.  These original parts are quite tough to find in the wild or even at swap meets!  If you've been looking for one to complete a restoration here's your chance.  The pictures tell the story.  It would surely beat making one!  I can be reached at 262 573 193 1 if you'd like to talk about it.  Good Luck.