Westerbeke is not actually a motor manufacturer, but an OEM that
assembles parts from other manufacturers, marinizes the resulting
motors, and sell them under the Westerbeke name. So the block could
well be a Perkins, or Matsubishi, or something else -- even 2 motors of
the same size might have different manufacturers. Here in the States,
there's no big problem, as there are numerous distributers (call
EnginesOne in Norfolk, VA ,800-548-6252), but if you go cruising abroad
you have to do some research to find out who made the original part, or
pay for an American dealer to ship it to you.