I have a Honda GCV160 engine that smokes at start up. The oil was a bit over filled. Not terribly. I fixed that and it still smokes a bit at start up. It goes away after 5 to 10 seconds. Passed a leak down test with flying colors. A little bit of air leaking out the oil fill tube. The valves are tight. Pretty normal for a mower engine in my experience. I am thinking it is worn intake valve seal. There is no head gasket on these engines because of the way it is designed. Am I missing anything?