You are going to need to plug the "Blue" circled nipple or the engine will not run well. Use a piece of Tygon and a plug in the Tygon. You can get Tygon fuel line at Glenn's in Shelby,

You need to have someone show you about about how all this works? This is from your description of the carburetor drawing fuel? About the pump side of the carb. The regulator side of the carb. Why you couldn't push fuel throught the carb. About the filter inside the carb.

You need to take the engine to someone who knows gas engines, chain saws, weed whackers, to have them explain how the Walbro type carburetor works and how important the engines crankcase being air tight is.

I live just north of your town if you want to come by my house I can show you how everything works and what is important and what is not? SENDMEAPM