I have a similar question (and i think some info would help the OP) I have a keg that I may have slightly overcarbed because of temperature. I thought the fridge was 40, in reality it was 36 @ 10psi. This leaves me at 2.5vols of co2. I have a foaming issue where its about a 3 finger head no matter what, and bubbles accumulate in the peak of the 10 ft lines. I was under the impression 10ft is longer than necessary, but not too long as to have negative effects other than a slower pour?
anyways, should I just disconnect gas and vent the keg for a day or two then put the gas back on? Maybe its overcarbed slightly causing the foam? I cant think of any other reason the lines are getting bubbles and causing the foam issue