Its where the metering plate mounts to the body by 4 screws. That is all after you remove the fuel bowel, then the metering plate, and check those 4 mounting screws that holds on the metering block on body.

_________________
it's like a vw, sounds like a million miles an hour but goes really slow. (for now)

BING!

Forgot you mentioned it was an Offy. Take the carb off the apdapter plate. The screws holding the adapter plate to the manifold can leak air.
I ended up putting RTV on the threads and screwing them in. Put it all back together, and report back!

CJ

_________________
Part of Tyrde-Browne Racing

UPDATE: Good news.

First, I have decided I have found the best (for me anyway) way of finding vacuum leaks, short of a smoke machine. I saw a post on a BMW site (they must have a real problem with vacuum leaks. I found a bunch of tidbits on BMW sites.) showing how to use a vacuum cleaner to pinpoint the leaks. http://www.bimmerboard.com/forums/posts/559025

I taped the vacuum hose to a garden hose and then taped that to my compressor hose (the flexible one) and hooked up the air nozzle attachment and finally vacuum line to the manifold port. Taped up the pcv. Saran wrap on the valve cover openings and the exhaust pipe. Put the Holley plastic hat that came with the carb on top. I used plumbers putty to seal it (mostly) to the top. Plugged the choke rod opening with the same. If you put the vacuum outside the garage and shut the door, it's fairly quiet inside. I should mention I have very good hearing. If you do this, you will need it.

I used fuel line as a stethoscope and kept going back to the unsealable leak at the carb top as a reference of what noise really was noise and not just the hose bumping something.

Anyhow, I could still get some noise from the secondary shaft, but not much. I thought I could hear some along the base on that same side and the intake side. That was about it. So I decided I needed to seal the gaskets to eliminate that.

One thing I need to mention. I don't know what others with the Offy manifold have where the stud that runs through the exhaust/intake comes up. On mine, the stud ends up above the level of the top of the manifold. Therefore, a hole is in the adapter to accomodate it. That made for some questionable sealing exacerbated by the Edelbrock twister that has a narrow rail on that side. Basically, the gasket could rise internally and externally to allow air throught he hole in the adaptor.

I bought two 1/4" base gaskets and one regular one. Sealed the hole in the adaptor. Cut a hole, but not all the way through, the one base gasket. Applied sealant all the way around the manifold surface, all the way around the adaptor surface, on the screw threads that attach the adaptor to the manifold (Thanks CJ. yes, the holes do go through), no sealant on the "regular" gasket top, no sealant on the top 1/4" gasket. I got the top/second thick gasket when I realized the accelerator pump arm had only .006" clearance with the regular one. The sealant I used is "High Tack" and was the only one I could see that was ok with gasoline.

FINALLY, tried it today. I can now idle at 700 rpm. I could go as low as 660 with the idle screw out completely, but I would like it to be functioning as a good stop. The secondary is "light barely showing" which is also 1/4 turn from nothing. If I took the secondaries out completely, I could probably go lower, but this is good for a starting point. I am going to leave it like this for a while to see what's what.

Thank you all for the good advice.

_________________
64 Valiant