Okay so I built a eagle 580 with a os 61 engine, its side mounted. It also has the old 7m carb, this is an old engine but ran great 3 years ago.

So I go to start it and its running lean, and dies when you throttle back, I notice the engine shuts off, the fuel thats in the line goes back into the tank, is this normal?
I am thinking tank setup is bad, but I dont know. Any ideas will help.