1976 yacht engine future, which way to turn?

[Mickeyrouse]

Having recently had my Westerbeke 55 rebuilt, I can give some number comparison. Parts and labor was about $3600. I pulled it and re-installed it. A new comparable engine was $16,000. Installation was extra. That roughly 1:4 ratio of rebuild to new may not hold, because while horsepower is more or less linear in new cost, parts and labor most likely isn’t. After all, it takes about the same amount of time to unbolt an oil pan and head, regardless of engine size.
Bukh engines have not been as used in the states as Yanmar or the marinized versions of Perkins, Isuzu, or Kubota, so our parts availability over here may be different, which availability is the go-no go question.
One more argument for re-build: since going back in with a different engine means that almost nothing will line up or match up, the engineering modifications to make a new different engine fit can easily be an additional half the cost of the new engine.

[Compass790]

I would do as skipperpete suggested. The parts prices for Bukhs are even worse than Yanmars here in NZ. I'd take an inboard diesel over an outboard any day & have had both. The Bukh 20 is a tough reliable engine WHEN MAINTAINED properly as another poster suggested. If you cannot do the work yourself it can get very expensive.