First off, is the carb for your ‘52 3600? What engine do you have?
The threaded connection is for a heat riser tube that comes from the exhaust manifold. There is a little casing that is attached to the exhaust manifold has a small tube that connects to the threaded portion on the carburetor. The heat from the exhaust (from around the manifold, not exhaust gases), as the engine heats, up causes the spring inside the black casing on the carb, to heat up and expand opening the choke plate. Take some pictures of what you have and hopefully we can tell you what you are missing.
Last edited by Phak1; 11/19/2021 1:20 PM.
