I just purchased an old Sea King Outboard. It's red and white. It's a 15 HP twin Cylinder. On the engine is an oval tag with "Evinrude 15028 08369" The woman that sold it to me didn't know anything about it. Would anyone know the year of mfg and the correct fuel-oil ratio? Thx.
Yes, that looks like it on the outside. It has three knobs on the front. High and Low speed set and a choke.
Your finding of what a 15028 Evinrude is was exactly what I found when I looked in Evinrude's website. The engine itself is bluish in color. Is it possible that someone at some time would have swapped out the original engine with the 18 hp evinrude? Would that engine fit in the 15 hp Sea King and properly attach to the drive mechanisms?
Well, Evinrude, Johnson and Gale are all divisions of OMC, and share many similarities. I have never attempted the powerhead swap that you mention, but obviously somebody else has and it seems to work. I am thinking there is a slight difference in the powerhead base bolts and gasket, but can't argue with success.
Anyway, to answer the original question, the oil gas mix is 24:1, whether it be the Gale or Evinrude powerhead.