The other day I checked on the Zenith carb's vacuum pull-off for the quasi-automatic choke, and made sure the piston wasn't gunked up. Well, I took the cover off the end with the 3 screws, thinking for sure there was a spring under there, and there wasn't one. Since Moss's catalog and the service books aren't showing the level of detail I need, is there supposed to be a spring between the piston and the end cap? I thought for sure there was, unless I lost it while I was servicing the carb many moons ago. The good news is I have a spare carb I could steal the spring from, but it's still packed away somewhere after my recent move, otherwise I could look at that one easily.