To Bob Z., post of Aug 15...
...With apologies, Kenn...
Mid-2000's, eh? I had a similar incident in the 1980's with a SIG fuel. That was long before the castor oil quality flap, which quieted down long before your incident.
Fuel still came in metal cans when mine occurred. I didn't much look at the fuel until after the flight when sparks came shooting out the exhaust and the (Fox 35) sounded very strained. Mine was also coked heavily in the exhaust stack, and the engine was "rather hot" when it came down, seized.
Near as I could figure, the castor oil had "turned". The fuel was black and opaque. I'd added about 5 fl oz to a new gallon of a SIG sport blend, and found that the entire gallon of castor I'd picked up to fatten sport fuels for Stunt 35s had 'gone.' Later, I read somewhere that castor oil CAN turn into a very dangerous form, highly flammable and dirty burning - or did I imagine that?
I did rescue the engine, but that flight sure wasn't fun. Fortunately, I was flying on a paved parking lot. No wildfire.
Today, we can see the fuel color through the plastic bottles. That was the only time I'd had a problem with SIG's AA Castor, and I still use it to brew up diesel fuels - as long as it is champagne clear... Diesels don't coke-up like glow fuels may, but I'm still thinking of trying some synthetic in the oil fraction...
Other fuel producers have had rare problems in the long distant past - like a batch of RC fuel that had no oil in it. Ah, history... worth learning so that we don't repeat its worst events...