Call Jim Cline, he's very helpful.
http://www.billsroom.com/pcfs/contact.htm

Is your tank buldging out really good and reaching a healthy pressure? It's hard to draw fuel without good pressure in the tank.

You can suck fuel out of the regulator using a fill pump but first make sure the tank is pressurized. The idea of running without the Cline is good but if the tank is too far back, and you go flying that way, it could lean out in uplines. It will rule out the carb if it runs without the Cline so it's its a very good test.