Anatomy of a webber carb

[moyest]

I'm running triple webber carbs on my car, with the simple sponge filters/socks over each air horn.

But just next to the filters is a small round hole in the side of each carb. I'm pretty sure I can see a jet when I look in there?? and the edge of the hole looks to be threaded - as if something's supposed to be screwed into it.

Is that hole supposed to be covered with a plug or filter or something? :stupid:

[240znz]

Don't block it.

From memory, K&N filter mounting plates have these holes in addition to the main throats.

Not sure if they are for the inlet of air for emulsion tubes and or cold start chokes.