Hi 41,
Had exact same problem expressed in an earlier post on about 07/18/2013 after just buying two (2) "new" starter switches.
My old & two (2) new switches were hanging up in the "ON" position whereby the pedal rod could not rise into the "OFF" position -- starter kept rotating while engine was running.
These new switches are hefty & well made; however, the small "circular" metal opening for the threaded female switch rod tube is so tight & small that the switch's threaded female rod tube angle cannot be adjusted.
Think all new ones from Vintique are like that.
Quick Fix:
1. Mount switch on starter & place a 5" high by 6" long piece of vertical cardboard immediately adjacent to the engine side of the switch.
2. With a pencil, very carefully trace the "exact" profile of the starter switch, the starter switch rod tube angle, & the starter pedal rod angle to witness that the starter switch rod tube angle has to be changed for proper alignment with the "operable" starter switch pedal rod when it moves up & down at an angle in the "ON" & "OFF" position.
3. With a Dremel tool & an abrasive cylinder, carefully grind the new switch's metal circular opening until it is elliptical; hence, such that the starter rod tube angle can be adjusted up & down in the enlarged elliptical opening to match the angle of the starter pedal rod.
4. Be careful to first get the "exact" angle required from your cardboard diagram so as to not make the switch's elliptical opening too large.
5. Worked for me -- little at a time, patience, & try until you get it right to where it cannot jam & stick in the depressed "ON" position.