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Discussion Starter · #1 · (Edited)
In my search for my next boat, I've come across a couple of boats that I really like but they had a lot of hours on the engine, from 4 to 6 thousand.

Both about 40 ft, early 90s sloops, one yanmar and one westerbeke.

Would an engine survey from a marine diesel mechanic tell you if the engine is in relatively good shape or is 5k hours just too many?

This is probably a hard question to answer but all imput will be appreciated.

Thanks, Jim.
 

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Bombay Explorer 44
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Will be hours not miles.

5,000 hours on a small diesel engine that is maintained correctly is not a lot. If it was 10,000 then I would be concerned. Some Perkins 4.108s have run to 50,000hrs on fridge units.

But it all does depend on maintenance and abuse.
 

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TQA. So I wonder how much info a mechanic could give on the condition of the engine.
Thanks for the edit.

Jim.
10K hrs. is the typical limit on these smaller marine diesels. Such an engine with 5K hours is only in 'mid life', IF the engine had good maintenance.

For a complete evaluation, I would suggest compression and 'pressure leak down testing'. Leak testing is by applying compressed air into the injector ports and evaluating exactly where the leaks are emanating from. Worn or defective Valves will leak either back through to the air intake or into the exhaust system, worn/defective piston rings will allow air passage into the crankcase, air being noted in the cooling system denotes head gasket leaks or cracks in the engine block - although 'black light' testing of the cooling water with a fluorescing dye is much better to determine head gasket leaks between the cooling circuits and the combustion chambers.

All that stated, be aware that the very 'older' models will probably not be any longer supported and their available replacement parts may become very hard to find. Example: 3QM, etc. Yanmar series.
 

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Yes, parts availability becomes an issue as they get older. It's becoming a real issue for my Universal - despite the fact it's going strong at 5k miles, in terms of wear.
 

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I think it also depends on what you are doing and where you are going with your boat. If you are daysailing/weekending from your own marina and not heavily dependent on the engine, and have access to parts and mechanics, then I'd feel okay with 5k hours.

If you are buying the boat to circumnavigate or to voyage to remote locations, then I'd probably want a newer engine.
 

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Good advice all around. One thing in your favor, is it sounds like the engines have not sat idle. 5000 hours/ 24 years above 200 hrs/year average. One of the worst thing for piston engines is sitting idle IMHO.
 

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Hey,

If the engine starts OK (especially when cold) and runs well (no excessive smoke, oil consumption low, no leaks of coolant or oil) then it's probably fine.

More important to me is how the engine physically looks. Is it clean and the block painted and dry? It is a dirty, grease and grime filled lump? Is the oil pan sitting in water? Is the case corroded and leaking? Can you tell by looking if accessories like the water water pump, fresh water pump, injectors, etc. have ever been replaced?

Personally, I would prefer clean 4000 hour engine that runs well and comes with maintenance records over a 1000 hour engine that is dirty and has no maintenance records. IMHO corrosion and lack of maintenance kills more engines than operating time.

Barry
 

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Discussion Starter · #10 ·
Thanks everybody for the input.
I asked the question because the majority of the boats I look at have under 1k hours. I'll be a little more comfortable with higher hours engines.
People don't seem to talk about it much, but a marine diesel mechanic going over the engine for you should be part of a survey.
Thanks again .

Jim.
 

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Trucks & heavy equipment get their oil analyzed by labs on a regular basis. Any outfit with big rigs can tell you where in your vicinity.

You need someone to explain the report to you though - I've seen them and they don't mean much even to an experienced layman.
 

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Agree on the mechanic.
Who does oil analysis? My own analysis would only involve smell and check for metal bits that settle out.

Jim.
Well the taste test can reveal a lot! I have used Blackstone, they are one of the big ones and generally give some explanation with the report. You can post results at Bob's the oil guy website they really understand oil there. Just keep in mind it may only give a hint as real info comes from trending the results over time.

Sent from my ADR6425LVW using Tapatalk
 

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formerly 'BoatyardBoy'
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We send oil samples on our generators on the diesel electric ship I'm on every 500hrs.. These tests can tell you more than a mechanic, as far as internal degradation and wear, oil quality and age, etc. Compression test can be done by you easily.

Sent from my HTC6500LVW using Tapatalk
 

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Discussion Starter · #16 ·
This is all good news.
I would think that getting your oil tested once in a while could only be a good thing.
I don't need the service yet, but I'm going to start looking into it.
Thanks again.

Jim.
 

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This is all good news.
I would think that getting your oil tested once in a while could only be a good thing.
I don't need the service yet, but I'm going to start looking into it.
Thanks again.

Jim.
One thing Blackstone will give you a free kit, with a collection vial and return envelope.
 

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One thing to keep in mind with a high hours engine is that sometimes it is an indicator of a boat used for charter--which can mean more wear and tear on everything, including the engine.
 

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I don't give much trust to engine hour meters.

Many boats (like my Pearson) don't come with them as a stock item. Most have had them retrofit. If I retrofit one now it would read 0, when my engine likely has 3000ish hours on it.

I've been on many boats that have an hour meter that doesn't work anymore. This is unlikely to be detected in an average survey and sea trial, where the time motoring on water is under an hour.

There are hour meters that don't really count hours and are timed with the rotational speed of the engine. So if they are calibrated to an hour at 3000rpm they would only show one hour of time for 2 hours of use at 1500rpm.

The hours aren't that important anyway. A diesel engine used for 10 hour days that is well serviced with 5000 hours on it will keep running that way for a very very long time (like the 30,000 hour example mentioned above). A diesel engine used for 5 minutes to get past the breakwater then turned off, oil changes every few years, and 5000 hours on the clock might be near the end of it's life. This would be typical of engine service times on many racing sailboats.
 
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