If all attmempts at mechanical cures fail, ArmorAll works great. I have an ARF with a no-foam tank installation and a vibrating engine (STG51) and use ArmourAll as an easy way to stop foaming. I've used it a LOT with no problems with glow plug life, engine problems etc.. At one time, I routinely added it to my gallons of fuel when I was adding extra castor. I've burned at least a couple of cases that way with no problems. Now, I'm more cautious about fuel tank mounting and don't really need it.
Add one drop at a time to your fuel jug, shaking vigorously each time. In a gallon jug, after somewhere around four drops the foaming after you shake the jug will suddenly and completely stop.
Good flying, Bob Scott