10k is not remotely the top end for a naturally aspirated 3208.
That said, if I were to plot a distribution of the number of pleasure boats with 3208 naturals, I would not be surprised to find that 7.5k hours were in the top decile. So what’s going on here?
Hours are simply not terribly causal to typical failure, people don’t really wear out a set of bearings or rings or even needing head rebuild due to wear. Nor will you see most boats ever get that high, failure or not. Yet you will see a lot of engine failures as the years climb at all kinds of different hours. Boats change hands before complete cooling system rebuilds and other expensive tasks and engines of all types do frequently suffer expensive bills.
Yet with 7,500 hours I’d guess a few things. I’d guess that boat is not running around with the original cast iron exhaust risers (which are now hard to get and expensive), and I’d even guess that the riser shower heads (the little holes that distribute the cooling water) are not clogged as most at half that number of hours will be. I’d guess that the heat exchanger has good serviceable end caps and that the cooling tubestack is not half clogged, again like many at half the age will be found. Simply put, an engine doesn’t go 7,500 hours without attending to some of the more advanced maintenance items that most ignore.
I wouldn’t be afraid of the hours, not one bit. I’d expect that a boat with half the hours would likely cost you $10-15k to get them into a condition where you have zero’d out the entire cooling system such that it could reliably do your trip. What you should evaluate is where this boat is at in that cycle. They may have done that last time 15 years ago and want to get out before the next investment, or it could have been last year.
The boat is likely fully depreciated, it’s not going to suffer in price just because of a negligible increase in hours and you will likely buy it at a bargain price. The question is if you buy a boat with lower hours at a premium, will that premium plus the amount of money you should spend to go through them be more money than any perceived depreciation upon selling. Surveys won’t disassemble the engine, so don’t expect a good survey on an engine with half the hours will mean you should not spend the money to zero everything. You more likely will need to do that. A set of risers all by themselves may set you back close to $5k.
So try to get to something more apples to apples in comparison. Hours alone will not tell the whole story. You will need a Lot more nuance than that.
