Plain and simple, it isn't drawing fuel. The mounting position and fuel tank position will not affect a pumper carb like the Walbro type on gasoline engines. "...i have been gone through the carb..." Did you actually dissasemble it? If so, did are you sure everything got put back together correctly? Several parts, including the butterfly, are position sensitive. If you took the carb and adaptor (if there is one) off the engine body, did it get put back the same way? There's a pressure port from the carb to the crankcase that's VERY important. Check for a clog in the gas line. Make sure the gas tank vent is open to the air, and not attached to the muffler as on glow fuel engines. Open the high and low speed needles about 1.25 turns. Choke it until there's gas dripping out of the carb throat. It should start and run.

Dr.1