When you say it drops the bottom pin when you pull the throttle,I'm not sure what you mean, but 'maybe' just maybe you are actually pulling on the choke mechanism, which has a linkage which will open the throttle blades a little but simultaneously shift the jets downward so it goes well rich. Any chance that is what is happening? in all seriousness, the linkages can look confusing, so you wouldn't be the first person to do it.