Ok thanks, so the yamalube and the amsoil will work, are you talking about the amsoil interceptor? I’ve seen that around.Nope you don't but it is nice not to have as much smoke that is for sure. Plus I have noticed lately the cost difference isn't much, in some spots around here 2 bucks is the difference in a quart and 3 or 4 bucks for a gallon. At that price even when I had early '90s sleds I would have gone full synthetic over the smokey stuff I was using. Prices sure have come down at least around here on it.