Does the automatic choke housing have a threaded fitting that a piece of 1/4" tubing can slip into? If so, that tube is probably coming from a sheet metal fixture attached to the exhaust manifold, not the intake. Its purpose is to draw heated air (Not exhaust gas) from around the manifold to assist rhe choke in releasing as the engine warms up. Some manifolds (mostly V8's) had a tube that went all the way through the echaust manifold and drew air through, heating it as the exhausy flowed around the tube.
Jerry
