TimR

I bought a jug of Sig Champion 15% (50/50 Syn/Castrol mix) Rc fuel because the store ran out of Cool Power (pure Syn) that I normally use. It ran OK a first, but then the low end side of the carb became fussy. Minor tweak and it worked fine. Nice low idle, not as fast high end as when I ran cool power.

My question is the exhaust residue came out black. But not mettalic as if the engine was wearing at a horrible rate. Is this normal?
Did I fry the engine?

The cool power exhaust was clean with a green tint to it. So I would think that the Sig fuel would be clear but have a pink tint. The fuel is recent.

Did I fry the engine.

Help.......

Thanks
Tim