my 36 scag witch is 4 years old started to tap the other day.we had just changed the oil a week before. now i have and open trailer witch we tarp at night.so anyway i check the engine and the oil is gray.right away i think water so i changed the oil again with the filter..i start it and the tap stops. so we pulled it out today and the same thing but the oil was not as gray , now mind you it was brand new oil.and we haven't had any rain.. so what the hell ???? ps starting to pop white smoke when we back of the throttle..