I acquired a Mercury outboard engine, it says Mercury 60, 6hp on it. As far as I can make out the serial number it says 208383. Can anyone tell me the year? I think I have it narrowed down to 66-68. It starts right up but I do not see any water discharging from it when ran in water. I have talked to some that say certain models do discharge from the center of the prop. What I have read it seems as though it should discharge from the engines exhaust port. Can anyone help?