Don't quite follow your hose-and-connection nomenclature!
Critical: Petcock to carburetor fuel inlet.
Carburetor vacuum connection to petcock.
With suction applied to vacuum hose, fuel should run freely from petcock to carb.
Simple test: Apply vacuum to petcock through vacuum connection hose; fuel should run freely from tank through petcock and carburetor fuel line. Or, yank the fuel line off the petcock and see if fuel runs into a container held to catch the flow. If you've got flow there, you should get flow into the carburetor float bowl hrough the main fuel line when the engine cranks.
Not sure? Open float bowl drain, use catch basin of some sort, and see if fuel flows from float bowl drain (after initial volume purged) when engine is cranked (both vacuum hose and fuel line connected up).
Assume you're aware; fuel will NOT flow from a stock petcock unless vacuum is applied.
Last edited by Damocles; 08-31-2016 at 03:44 PM.