Nice looking motor! It looks like a 1st year model, a 1952. The decals look like the original lacquered type. Make sure you run at least 24:1, even if you run synthetic oil. It is a bronze bushed motor and it needs the oil film thickness to keep it from wearing out prematurely. Never leaner. Originally I think they said to use 16:1 but that was with old fashioned straight 30 weight oil.
OMC used to sell an accessory kit that someone here earlier described. It's release coincided with the 1964 models. It allowed you to use the integral tank or a regular non-pressurized single line tank. Using a 6 U.S. (5 Imperial) gallon tank would give you 12 hours of operation at full throttle or 17 hours at a relaxed cruise (whatever that means with 3 horsepower).
Part # 381475 for the complete kit as of 1967. There is an old Evinrude dealer in New Jersey that I have had luck in finding old stuff; Van's or something like that. Now you can search.
