Just to put 2000 hours into perspective; this is about;
1 hr a day, 5 days a week and 4.6 hrs every weekend for 4 years. or
1.6hrs a day,5 days a week, and 4.6 hrs every weekend for 3 yrs.or
for summers only;
10 hours every a weekend for 20 weeks per summer, for about 10 years; Kindof what a boat might do. A lot can happen in 10 years.A boat might sit in the water from Friday evening until late Sunday afternoon, say about 40 hours. And it will probably be a start and stop deal, every couple of hours, and it will be running over 3000rpm for a good deal of the time. If the cooling system is lake water, the engine may never come up to a decent temperature. The rest of the time, the boat sits, with the cooling system sortof open to the atmosphere.
On the other hand, it may have had an independent sealed cooling system, and may have been running some form of additives. I have worked on both kinds.
