Anyone ever . . .
 

. . . fitted a ducted fan unit to the carb of a largeish model engine to supercharge it? Crazy question perhaps, but the idea occurred to me earlier. Presumeably, if the mixture was richened up a lot, it could boost performance?

RE: Anyone ever . . .
 

Axial flow fans aren't very good at compressing air in a single stage but presumable you could some kind of performance increase, probably not much on a two stroke though.