Originally Posted by
randylervold
Jason, the two failures Jon mentioned were not in the US, rather the middle east. Therein lies the problem -- in the US our mogas is consistent and refined to a standard we know, but when you start getting into other non-US markets it's jungle rules (no pun intended). With it's 9.0-1 compression and it's double electronic ignition with more advanced timing than magnetos you get a challenging environment for preventing detonation with fuel of unknown octane. Then of course there's the ethanol issue.
Indeed quite a few CC340 owners have used PREMIUM mogas in the US with acceptable results, but we can't and won't recommend it because 1) we have customers all over the world with dubious fuel quality, and 2) the well documented dangers of ethanol in aviation applications.