This is a 2-stroke engine which uses a gasoline/2-stroke oil mix. The carb is probably a Walbro type. It has an internal diaphragm which operates from crankcase pressure through a port in the manifold. This pressure/diaphragm actually pumps fuel into the engine. Gas tank position is NOT critical, and no gasoline tank pressure is required.

Weedeater engines are not gravity fed. They utilize the same pressure/diaphragm system I just described.

Dr.1