I want to buy a motor in the 9.9 hp range and of course they sell both 2 strokes and 4 strokes. I'm curious what are advantages and disadvantages? It seems like it would be a pain to always have to buy the oil mix for the 2 stroke. I remember someone telling me that one is louder then the other... but I don't remember which. Are they both about the same as far as fuel efficiency? What about maintenance difficulty/cost? Right now I am leaning towards the 4 stroke... but finding a used one in my area may be difficult and may just have to go for whatever is available. Any help would be great... thanks.