Wilsons Sandbox

Messing with my petcock here...got it all apart and it "looks" perfect except for one thing. The straight thru vacuum port(that goes to the center of the casting) looks clean on both ends except I can't pass a .020 safety wire thru it. Now that's a sizable port on both ends...I am wondering if it necks down in there where we can't see to something like the little tiny port that's 90 degrees to the fitting(p 185 fig 56 in my Cylmers)or if its supposed to be the same size all the way thru. Thought I'd check with the petcock experts before running a bit or something thru it to open it up. This thing quit on me in the worst neighborhood in town...ran out of gas on ON and switched to RES and it wouldn't feed. The screen looked clean and nothing stopped up that I could find. Blew it all out with air and inspected it real careful like. Nothing. Tell me why it won't feed on RES please. BTW a couple of the resident street thugs pushed it to the gas station for me; I guess there is some advantage to being old and pitiful looking. One other thing...after looking at the million micron screens on the standpipes I can't see much need for an external filter. I tried one on mine a while back and it wouldn't feed all the way to empty so took it off. I did a search. Thx Joe