Year of evinrude

[slimjim816]

I have recently acquired an evinrude engine that i believe to be an 18 hp but not sure of the year the engine seems to run great but is leaking around the prop shaft the serial # is 18502S-E06123. I plan on changing the water pump impeller and shaft seal.I also will be using this on a 14 ft aluminum boat could someone tell me what year it is ?