It appears that you're getting fuel, because it runs if you choke it, you're just not getting enough fuel. You need to find out why it's not getting enough. I would start at the fuel tank and worked my way through to, and through, the carburetor. There must be some kind of blockage somewhere. I say that because a lot of people are using a .038" jet, it should be enough to allow the engine to run.
I've heard of people having trouble with the mounting of the carburetor. An air leak can be an elusive thing.