Thanks Stoker. That's the big question remaining in my mind--does this governor really have any control over amount of steam input, 'cut off' position, etc.? The German catalog description seems to imply that it does. Maybe some experimental fixing of the balls at different positions and then measuring rpm would reveal the answer. Presumably the higher the speed (balls out) the more the valve piston would be withdrawn from its cylinder, but I'm not sure that's the case. Maybe a slow motion video would help. Ideas welcome. If the governor has no such function, then why the springs--why not just a spinner like most of the other toy engine governors?