RE: FL 70 4stroke
I've had a couple of these and my luck has actually been very good. They just don't like to be inverted since the carb is an air bleed type like the .40-LA. when inverted you are always fighting a rich mixture at idle. You also can't reverse the carb which can be a pain with some installations. On a simple sport airplane with upright or sideways mounting though, mine both did well.
I ran 10% fuel with no problems but 15% might work well too.