It's normal but some fuel has more oil and a different blend then others. I just maidened a plane this week and it had a brand new engine too, a maiden for both. I had more oil on the plane then I have seen on any of my planes ever before. Thick as snot!! I think part of the reason was the fuel I was using only has 16% oil and the other engines I run should have a bit more oil in the fuel so I added 2 ounces of Klotz oil. It is also a blend and has 20% castor in it. The new engine is a two stroke so it seems to blow out more spent fuel then my other four strokes. {YS} Clean up was nasty but I know the engine was getting enough oil, better safe then sorry.