If the engine still is bone dry, the carb is clearly not admitting any fuel. I still am puzzled why the test stand gets wet though.
Since you are new to gas engines, this is not a remote help case.
Get someone more experienced to look at your carb (probably a sticking fuel needle). To unstick the fuel needle, reconnect the line to the sheet metal cover and blow pressure in it while you have the choke closed and flip the prop. This should unstick the needle and prepare the new carb for operation.
Look in this forum and search for "carb not pumping fuel" and like posts. It is a common problem with Walbro carbs, to the extent that the carb needs replacing.