'During leak down at 100 psi the barrel valve will not give a reading on the 2nd gauge. ' I'm confused.When you set the at 100psi on the first gauge-with out conecting to the barrel valve ..the second gauge should read 100 psi. then when you conect the tester to the fuel inlet line on the barrel valve-what does it read?0-100 psi, it can't 'not give a reading'....to answer your other ?..a barrel valve rotates one way-you expose a portion of a hole to set the valve at idle but when the arm link is turned the proper way it exposes a ramp that widens as it coninues to rotate -allowing more fuel to be feed as the throttle opens....someone may have assembled the barrel valve wrong or put the linkage on backwards......