I am running the OS bubble less clunk like I run in all of my tanks. The fuel tank is a three line system and it is the stock tank that came with the GP Pitts S-2. I really suspect that the line has come off inside the tank. I have a a flairing tool that I can flair 1/8 tubing so I will do this tomorrow and wire everything on. As far as the tuning goes since I am new to gas how does it differ from glow? It is easy to tune glow but gas seems to be a different animal. I have good ventilation into the cowl and my buddy has the same motor in a GP Ultimate and his engine is a cool as can be after the flight so I really am suspect to the plumbing. Like I said I will let you know tomorrow when I yank that tank.