Looking for idle speed screw - Zama M1 M7

[rx7haze]

I'm looking for an idle speed screw for a Zama M1 M7 carb which is (or will be) on a McCulloch MiniMac 6. My local parts guys just laugh at me as soon as I mention this saw and dismiss it at worthless. It was my dad's from the 70's. He used it to maintain 1/3 acre in the burbs so it's got very few hours on it and probably quite a bit of life left in it.
Any help would be greatly appreciated.
Thanks, Bill