I just installed an "Iron Bay " fuel regulator on a Saito 220 mounted inverted. The engine is brand new and so is the regulator. I hooked-up the regulator according to the supplied instructions and it appeared to be working at 1/4 throttle. I ran the engine at this setting for 10 minutes to break in the new components. On the second run I advanced the trottle to half and this is were the problem starts. The fuel line from the regulator to the carburator fills up with air bubbles and the engine starts to die. Moving the throttle back to the 1/4 setting the air bubbles dissappear and the engines runs fine. I tried adjusting the needle valve from lean to rich and it makes no difference. Do I have an air leak in the regulator or could it becoming from some other place. This is my first regulator and I'm asking for help.