I'm not 100% sure but I would think that the F8 has a similar scavenging/PCV circuit as any modern, emissions regulated motor does.
I'm working overseas right now so I can't check mine, but I would bet that (to differing degrees of course) most F8's will have some sort of oil residue in the airbox.
I'd be more worried about fixing the sputtering and stalling first, then keep an eye on the oil levels after it was running correctly.
Hope you get it sorted out - my money is on bad fuel as well.
Just my $0.02.
My apologies to the meek and the Earth they will not inherit.