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Discussion Starter #1
Does anyone know the purpose of the little screw between the progression hole cover and the idle adjustment screw on a Weber 40 DCOE 28? (Pic below, two per carb) It's not in any of the parts diagrams I've been able to find, though it does appear in online photos of '28s. It also is shown in a drawing in the owners manual, so I believe this is original to the car (1971 Giulia 1300 Super). From the position I'd guess something to do with the cold-start circuit. There appears to be a drilled hole, suggesting some sort of air bleed, but that seems like a pretty dirty place from which to be drawing air. Anybody know?

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But Mad North-Northwest
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I believe that's the port for a vacuum takeoff. You'd use it if you wanted to hook up manometers.
 

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Premium Member
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Discussion Starter #3
Sure enough. Armed with a bit of confidence that springs and ball bearings wouldn't leap to freedom, I took one out and yes, it appears to be just a plug for a port into the barrel. The drilled hole in the top of the screw doesn't go anywhere, and while shining a light in the input side of the carb barrel with throttle open, I can see a dot of light through the hole. Mystery solved.

Thanks for the help.
 
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