It provides tension but if you look at the shaft there is a slightly necked down area for that spring plunger to rest in when gear is fully retracted. That keeps the gear from wandering out of place when starter is not being used. Say what you will about these Bendix drives but they are clever.
You will notice a lot less vendors since your last visit and a lot of unused spaces. There is still stuff to be had, you just have to work a little harder. Enjoy your time there!
Today's society doesn't really care about older things. The focus is on new, new, new. As a result we lose sight of how we got to where we are, the Model A is a vital piece of that journey.
There are also rubber pads used with that wood block. The dip is just about on the frame, a thin rubber washer is used under it.
Maybe someone will post pictures if you are lucky. :)
It is an adjustable main jet. Sort of like the GAV on a Zenith but not accessible when driving. Because all the fuel goes through it at cruising speed you can't shut it off like a GAV. The secret is knowing what the base setting is, how many turns open from being seated shut. I don't know myself.
It is important that the piston ring grooves (lands) are not worn excessively to let the rings move up and down in the piston. I would recommend a "dingle ball" style hone to break the glaze with minimal wear to cylinder wall. I have re-ringed a lot of old motors over the years without a...