trying to figure out the fuel system on 71 midget

First of all, want to thank all of you for the great help. I either always get a good answer, or at the least, am pointed in the right direction to find it.
Here's my problem now (taking a break from the electrical stuff for a while)
it's a 1971 midget m3 with the 1275 engine. There is the 2 zenith stromberg carb assembly. What Im tryin to figure out (bear with me as I am not sure of the technical terms) the small manifold for the carb assembly that is attached between the engine and the carbs? (it looks like a tube with several fittings) there is a nut fitting with a metal tube coming up out of it (towards front of assembly) that looks like it is intended to be attached to a hose. what was on it when I got it was what looked like a piece of small black hose with a flat-top screw in it as a stop. Now, behind this (a couple inches further back) is another bigger black tube that goes 90 degrees, and this also has what looks like a bolt with a hose clamp to stop any leaks. Engine runned fine, but after loosing this first (up-front) piece of hose, the car runs like crap. If I plug the hole, the car runs fine... what I am trying to find out is what this does (is it a vacuum hose to recover and re-burn exhaust? or some sort of smog thing) and I am guessing that this is not the correct way it is supposed to be assembled. Unfortunately the manual I have doesnt show it and I cant seem to find any diagrams anywhere else. ANy suggestions would be greatly appreciated.

Chad,

I think what you are describing is part of the emissions system. Has all the emissions stuff been removed from your car? If so, just plug the hose and drive on.

Others will have more specifics about where that hose used to go.

BTW, the 2 carbs on the 1275 are SU's. The ZS was a single carb on the later 1500cc engines.

Bryan

One of the best ways I found to figure out were such things go is looking at the Moss or VB catalogs. I spent many hours when putting my midget back together from scratch by looking over these two catalogs. Lots of times I'd say "Oh that's what that is or that's where it goes".

Another good source was looking at engine compartment images. Good luck.