Tetra, all of the
advice above is good, and Sailorchic's input is gold...if you get to the
purchase point.
Mark makes an excellent point, depending on what exactly you're contemplating
purchasing. Assuming based on the
engine that it's a 30-35'er, a new
engine install may well equal the
purchase price of the
boat. So following the install you'll be the proud owner of a
boat is worth 50-65% of the
money invested in it, assuming you're
buying it for market value.
As noted, the general
survey is going to tell you very little about the state of the engine, other than it runs within general spec (rpm, temp, etc.) and what a visual
inspection reveals. An engine
survey would be worth the
money given there are no
logs or
history, particularly if you don't have any experience with diesels.
If that reveals the engine to be in decent shape, just use it, maintain it, learn about it. You'll be in a far better position to then determine down the road what your needs and options are.