Topgun, the only way the 9 PSIG will not flatten the beer is if you have both a very low carbonated beer (2.2 vol???)
and your temperature is very cold (32-34 F).
As to the first post, what type of beer do you have? Liquid temperature? Length of 3/16" ID line? Elevation? Are your mugs frozen? etc.
Scott Zuhse, Instructor
Micro Matic Dispense Institute