I have a 15 Hp V-Twin Kawasaki FH451V engine on my Bob-Cat mower (which I love!!!!!!!!). Here is the problem I have noticed that sometimes when I start the engine it blows some white smoke for about 10 seconds. It runs like a great and the oil level is ok. It only blows smoke when the engine is choked. I also noticed that a tiny bit of some kind of liquid seems to be coming out of behind the air filter. The air filter is clean and the engine has about 50 hrs on it. Is this normal, what causes it?