I just changed the lube in the lower unit of my 1976 35 HP Evinrude for the first time in 20 years, although it hasn't been used in the last 12. I have always checked it seasonally and never noticed any problems. When I just now drained it, the lube had no milk nor water in it, however there were some streaks of black, like might come from the exhaust. Is this cause for major LU overhaul, or somewhat normal?
