So I did the 20hr oil change on my new Yamaha F115 4-stroke yesterday. The oil was was darker than I though it would have been but when the last few ounces was draining out I could see streaks of a lighter color and it smelled like fuel. Is this normal on the first change? It never seemed to be enough to raise the dipstick level when I checked it during the first 19.5 hours. Thanks