One dune trip, my 3 four strokes popped lean on the top end, my 2 strokes had noticeable increase in EGT and completely burned out packing,and my fuel station on my toy hauler pumped 5 gal then the very next day pumped 10 drops and seized up, pulled the pump head apart to find a thick amber goo. On retrospect, that was all Casey's Conveniece store premium and I'm not to sure they stick to the 10% max. but really, Goggle it, the 2 stroke boat mechanics blame it for everything.