On the Rochester, here are a few things to look for...and a few surprises I found when looking inside the 5 I used for the study: A. Parts of the airhorn. 1 the float, 2 the main jet, 3 the power valve...this one had been stripped and had an o-ring installed in an attempt to make it seal (which pretty well made sure it wouldn't work right any longer, 4 the main well housing assembly, 5 the power piston, 6 a vacuum tube (could have been knocked off by the rebuilder, 7 crossbar / air bleed, 8 idle fuel passage, 9 vent hole B. If the pump isn't shooting fuel in the manifold, please pay attention to 1 and 2 in the second image. Also the passage leading into the bore for the fuel. And be certain the correct pump type was used. C. Make certain all these little holes are clean and open (3rd image) D. You may have this vacuum hole scheme. Your gasket may cover one of them. (4th image) E. At this point your fuel inlet diameter could be any size at all. It is all a matter of chance and it matters what size it is. Carter specified the inlet size in all their carburetors. If Rochester ever did that, I could never find the data. Too large? You risk flooding. Take a look at what I found (5th image). Good luck. Please let us know if you have questions.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
