Awesome info StarTech. Exactly what I was looking fo'. I've never been inside one of these carbs yet other than removing the welch plugs.Why? They are non-replaceable parts. The jet is also pressed in place.
If you have a clog in that area you remove the two steel balls by drilling them out so they can be extracted. (Both in the tower) Then you replace them with a 7/64 (.109") or 3 mm (.118") steel balls; also can use brass screws that fits and just goes the depth of the metal then file level with the metal. I had to clean out several with heavy clogging with rust and other junk because of the rusting metal tanks with ultrasonics. I have found the passages can be very clogged. One is drill straight up to where adjustable mixture screw (sometime fixed mixture) goes. The other is crossed drilled above the main jet.
Note if the metal tank is heavily rusted just give up in my opinion; unless, you got a non rusted tank. These tanks are NLA. Many of these tanks have anti splash material inside them that is damaged by rust removers.