So today is June 21, 2016. Due to ongoing and increasingly inconvenient symptoms w/ my Subie, I just finished working on the Weber 32/36 DGEV carb. Hard hot re-starts, and a tendency to want to stall on hard left turns, led me to suspect a bad float. I bought a new float, inlet filter screen, and had a needle/seat set onhand.
Though I didn't get pics, first I'll say the original float weighed 20 grams, while the new one weighed ten grams. There were fine black particles in the float bowl, and the plastic(!) fuel inlet filter screen fell apart on removal. This plastic screen was discolored light brown, and the plastic material was brittle. The black particles I think were tiny bits of plastic off the original float.
I think, that my use over time of MPG Remedy was the culprit in all this. Seems like the float black plastic and inlet screen plastic were attacked by the MPG remedy. The float likely absorbed some fuel (they are known to be vulnerable to this), gained weight and caused an over rich condition. I had made a number of batches of MPGR, and probably used too much Anaprin aspirin powder. This I think made the "acid" Dan Merrick spoke of originally in the fuel.
So, my current opinion on MPG Remedy is- I think it can be fine for fuel injected engines, just be cautious how you make it, don't use too much aspirin. That will make it too chemically "hot". For carburetors, either skip using MPG Remedy, or be extra careful not to make it too "hot".
With all new fuel inlet system parts, plus a new fuel pressure regulator, the Subie is a happy little beast again!
Tracy G