Thanks Loren. I have heard of the Yanmars. Yes my boat originally had an atomic 4 I think. Im sure a 2 cylinder yanmar would fit. Not sure about the transmission and or how much it will cost.A friend of mine repowered his E-27 with a single cylinder Yanmar, many years ago, when the original A4 died.
The only (minor) regret he ever had was not putting in a twin.
Does your boat have provision for an inboard, from the factory?
I would bet that a modern two-cylinder diesel would fit very well.
Another way to view it would be to find an engine of around 14 hp or so. I like the Betamarine product, but lots of sailors are happy with Yanmars too.
There are several of us "vikings" that have posted up our Betamarine repowering projects here in the last several years, one was in the San Juan's. You should peruse these stories to get an idea of what goes into this. I equate it to re-rigging a sailboat, mast and all.... i.e. changing out one of the two main profusion systems that the boat has. I have several blog entries about this.
If you love your boat, this will go far to making it "like new" for a fraction of the cost of a new sailboat of similar displacement, quality, and function.