ORIGINAL: k3 valley flyer
I ran OS FP 40s on 15% Cool Power for years with no problems as did many other members in my club. All castor oil fuel did was varnish them up. Any engine can be run to lean but if tuned correctly the synthetic fuel worked just fine.
I see new ABN OS LA's trashed with regularity at my field by people running Cool Power. Before they get even an hour running time on them the TDC pinch is gone and the compression so bad it will only start with an electric starter. People using starters can't even feel when their engine is toasted, they just notice a worser idle and higher fuel consumption.