Edelbrock accelerater pump

I assume that you are totally disassembling the carb when cleaning? If not, then I would not be expecting to get it fully clean (assumign that is the issue). With this being off of CL, I would be stripping it ALL apart to clean, and inspecting for cracks, loose venturi mounting, bent/binding metering rods and linkages, etc.....the seller could have sold for problems other than he stated.....gee, that never happens, right? And there was a recent thread here about a casting/machining issue in the base of one of these carbs......

The stronger staging spring makes sense with the higher vacuum readings, but I don't think that is likely the issue; if you are fuly opening the throttle from idle when sitting; the vacuum is dropping below even the lowest staging spring setting, and certainly the stongest one (at 8" Hg) and the metering rod is doing its thing in moving. The way the video sounded, it seems like there is very little extra fuel getting to the engine for the air.

Dumb questions: Are the secondary air valves closed at idle? Have you looked into the secondaries with a mirror while trying this quick throttle opening and seeing if the air valves stay closed? I would expect them to stay closed in this light load condition of opening the throttle when sitting still. And is the einge warmed up when you try this? (Is there a choke on this carb?)

And BTW, I am no expert on these; I am just reading the manual on how it works and applying my Holley and Weber and general carb experiences to try to help. (Carb's work pretty much on the same principles....) Any experienced Edelbrock guys should lend their expertise.....