Unfortunately I have seen the same happen several times:
Sailboat is sitting still for a few years.
Gunks grows in the diesel
Boat sells, new owner does not clean tank.
New owner takes boat out.
Rocking and rolling breaks loose the gunk.
Gunk clogs filter, engine
stops, boat on rocks.
I took the job of prepping a boat for an Atlantic crossing
years ago. The boat (Harding 44) have been sitting for 3 years.
Told the owner to send money
for fuel tank cleaning
Told the delivery
crew they would run into problems and to carry
a bunch of extra filters.
Sure enough, the engine
stopped out there and they had to sail into
some port in the Bahamas
and get the tank cleaned at 3 times the cost.
Seen it over and over again, owners in denial.
(Not saying this was the cause on todays thread, just tossing out a free wake-up call in case there is ignorant owners out there who are counting on their motors to run like a Swiss watch all the time)