Every time I fly I have some oil on the lower cowling around and mainly just behind the air filter. I couldn´t locate the spot where it comes from as the air stream inside the cowling is probably kind of disturbed. Only thing I can tell is the lower carb is always wet with the oil. It is a C-90-14F and I was told by other SuperCub pilots that this is normal. Don´t want to believe this however and asking for someone else´s experience.