Hi there this outboard was made in 1964 hope that helps you
paid 150.00 for a 1972 in perfect shape
24-1 until 1964, then 50-1
On average 1 HP Equals 25-30 lbs of thrust Depending on Prop Pitch. So a 15 HP would give you 450 lbs of thrust. I had a 18HP Evinrude Fastwin on a 14 ft Aluminum Jon Boat that would get water ski's or Hydro Slider on plane.
The year for the 15020 model of the Evinrude Fastwin is 1957 and it has 18 horsepower. The 15541 is a part number for the model of the motor; it is the e-force universal carbureted supercharger kit.
As best I can remember, the 18 hp Evinrude was discontinued in the early to mid 1970's, so we are talking 30 years old. There may be some collector interest, but basicly in the 150 - 350 dollar range would be fair.