Wow! That is alot of gas in the beer. Keep bumping up the pressure until you do not see any bubbles rising just above the coupler. Quickly open and close faucet before you look for bubbles (use flashlight). We had this similar issue in a workshop with a highly carbed beer and ended up with about 30 PSIG with lots of 3/16".
Alternative would be to shake down the carbonation. Why does this beer need so much in the first palce. Is there that much second fermentation going on?
Scott Zuhse, Instructor
Micro Matic Dispense Institute