Buying a boat. Engine hours?

[boatbrain]

Hi,

I don't want to get in a controversy, but I seriously wonder if you need to change oil if you have not run your engine very much.

You hear the claim that the main breakdown of oil is due to high temperature, if it's true, the oil is not wearing out while sitting.

Also, you hear the claim the oil get's acidic, but oil is supposed to have buffering agents - and so it resists changes in pH.

I also question the claim that running the engine under load before it's fully warmed up is harmful -at least with cars, they tell use to run them, slowly in order to warm them up, and finally, the claim that a shutdown without a cooling cycle is harmful - again, with cars, almost no one does that.

Not trying to offend anyone, but I can't reconcile the claims with the advice being put out to car owners.

Also, I am wondering if running the engine causes faster corrosion in any part of the cooling system? You see the claim that car's water passages will corrode due to the motion of the water setting up electric currents.

Again, I am just curious as to responses, not trying to get in a dispute.

[svfraidknot]

when i bought my 42 solaris 1978 the motors " 50 HP YANMARS " had recent rebuild one 600 plus the other like 450 plus hours on them. i now have 1015 on one the other says 700 but about 100 hours ago i got bad fuel after couple of thousand bucks . rebuilt pump new injectors new lines , new rings, new gaskets etc like new motor again ,, on advice of mechanic i replaced the "original " raycore fuel filter system and lines at a cost of about 800 !! my buddy is a diesel expert after checking out the motors before i bought my boat he agreed the motors did indeed seem to be like new and in his opinion the old " industrial" motors i had could be run tens of thousands of hours before rebuild and could be rebuilt cheaply and many times if need be .. his advice same as here , change oil regular basis , run weekly or every other week at least , run to operating temperature under load and out . you can hardly get off the key fast enough to start my motors .. selling my boat it is listed here .. my advice get a good mechanic to check out the motors and if he is like me has a log book for every hour , oil , fuel , filter change .. i have seen motors half the size of mine probably weigh half as much but i would not trade for one of them .. old yanmars are so simple and my boat is so big and so heavy the additional weight dont matter ..

[a64pilot]

Originally Posted by boatbrain

Hi,

I don't want to get in a controversy, but I seriously wonder if you need to change oil if you have not run your engine very much.

You hear the claim that the main breakdown of oil is due to high temperature, if it's true, the oil is not wearing out while sitting.

Also, you hear the claim the oil get's acidic, but oil is supposed to have buffering agents - and so it resists changes in pH.

I also question the claim that running the engine under load before it's fully warmed up is harmful -at least with cars, they tell use to run them, slowly in order to warm them up, and finally, the claim that a shutdown without a cooling cycle is harmful - again, with cars, almost no one does that.

Not trying to offend anyone, but I can't reconcile the claims with the advice being put out to car owners.

Also, I am wondering if running the engine causes faster corrosion in any part of the cooling system? You see the claim that car's water passages will corrode due to the motion of the water setting up electric currents.

Again, I am just curious as to responses, not trying to get in a dispute.

You know I'd agree with pretty much everything you have said, US Army went to SOAP which stands for Specialized Oil Analysis Program probably 30 yrs ago, not for what people think, but to change oil when it showed evidence of breakdown, and some engines go years before the analysis says change it.
But oil is cheap, and is the best when it comes out of the can from there is slowly degrades, so I change it often.
Practices you state are for people who are trying to maximize the life of their engine, most automobile drivers never see 100,000 miles out of a car, they sell it first, but for those of us that drive one til the car falls apart following your practices is best.

I've never heard of the cooling systems setting up electrical currents though


Oh, and you change a Diesel's oil not because the oil is broken down, but because it laden with soot, you change it to get the soot out, oil is almost always fine, just dirty, and soot is abrasive

[MarkSF]

Originally Posted by boatbrain

Hi,

I don't want to get in a controversy, but I seriously wonder if you need to change oil if you have not run your engine very much.

You hear the claim that the main breakdown of oil is due to high temperature, if it's true, the oil is not wearing out while sitting.

Also, you hear the claim the oil get's acidic, but oil is supposed to have buffering agents - and so it resists changes in pH.

I also question the claim that running the engine under load before it's fully warmed up is harmful -at least with cars, they tell use to run them, slowly in order to warm them up, and finally, the claim that a shutdown without a cooling cycle is harmful - again, with cars, almost no one does that.

Not trying to offend anyone, but I can't reconcile the claims with the advice being put out to car owners.

Also, I am wondering if running the engine causes faster corrosion in any part of the cooling system? You see the claim that car's water passages will corrode due to the motion of the water setting up electric currents.

Again, I am just curious as to responses, not trying to get in a dispute.

I believe that it is better to drive the car GENTLY to warm it up, rather than by idling, as this reduces the length of time that the engine spends in the harmful cold state. I placed the emphasis on gently as that is the key factor. In a cold engine there are two issues : parts that do not fit properly until they are warmed up, and oil that is very viscous. Placing a heavy load on these parts is asking for trouble. Such trouble is rare, but very serious - spun main bearings are not funny.

Note that oil temperature will lag the coolant temperature by at least 10 minutes, so I will never use full throttle in the car until at least 10 minutes after the coolant temp reads medium.

The same could also go for the boat. I start my engine and run it for a couple of minutes, then finish warming it up in gear but progressively increasing the load over 10 minutes or so. They do exactly this with large ship diesels.

For cars, the cool-down is also a good idea, but does tend to happen somewhat automatically. Most journeys end with a period of light load - parking lots, residential streets, and so on. That doesn't happen so much with a boat - you can go from cruise power, put up the sails, and turn the engine off. I always idle mine for a few minutes before shutdown.

Large turbo-diesel trucks will not turn the engine off until the oil has cooled past a certain threshold.

The point here is that appropriate warm-up and cool-down are good practice. The fact that modern engines are so well engineered that they mostly tolerate bad practice, does not alter the fact that those practices are bad.

Will one person see any difference? Maybe not. But if a million car drivers were to be sampled, I think you would see a strong statistical correlation between engine problems, and warm-up/cool-down practice.

[JPA Cate]

Originally Posted by sunxpert

The major maintenance thing is oil and oil filter change. How often that should be done? I change my oil every 10000km in my car, but hard to tell how many engine hours is that?

The answer to that will be in the engine's manual. There is no industry standard. Many want that change at 100 hrs., but others (like our Nanni marinized Kubota) the interval is 200 hrs. It seems likely that still other others will have other intervals.

Ann

[a64pilot]

Oil is cheap. I do it every 100 hours which until we go full time is about once a year.
Just as a reference aircraft without an oil filter, 25 hours, with oil filter 50 hours. I only bring that up for those that will say 100 hours is ridiculously short.
Average automobile I believe is 30 mph, if that's true then 100 hours is 3000 miles, the old standard. Our Prius tracks and displays average speed and it's usually right at 30 mph, but we do a lot of highway driving.

New modern oils I'm sure can go much longer, but oil is cheap compared to engines, and old engines need oil changed more frequently than new ones, due to more blow-by, but old engines tend to get less frequent oil changes.


Sent from my iPad Pro using Cruisers Sailing Forum

[SaltyMetals]

I shared a Beneteau Oceanis 400 (1992) for many yrs with a friend. In fact she is hull #1. Now has about 3,500 hrs. It is a Yanmar 48Hp. Never had to do anything more than change oil & filters which was always done within the Yanmar recommended hrs. Will probably be the same reliable engine after 2x or 3x these hours.

We always service according to Yanmar schedule, warm up and allow a cool down period. Even if the engine needs to be used to charge batteries when at anchor the boat is put into reverse to apply some load to the engine. Look after the engine and it will look after you. Your problem is that in buying a boat second hand you have no idea how well the engine has been treated over the years. I wld stay away from charter boats.

[ramblinrod]

Originally Posted by sunxpert

Ok, guys. Thanks a lot.
Probably not worth judging a sailboat general condition based no engine hours.

There is no magic number where it is guaranteed OK, and either less or more is bad.

But here are some thoughts, based on my experience with boats (marine service provider) in an area with a 6 month boat season.

A boat that only gets 20 hours per year, is barely used.

A lightly motored boat gets maybe 50 hours per year.

A boat that has had 200 hours per year put on, has been motored a fair bit.

A boat with 1000 hours per year on it, gets motored A LOT

So if an 8 year old boat has 160 hours showing, it has hardly been used. It will likely be as it came from the factory. (The owner doesn't really like sailing.)

If an 8 year old boat has 400 hours on it, it has been used fairly regular on weekends and vacations. If it has been upgraded some and kept in good shape. This is a great boat to buy as it hasn't likely been hurt, but it won't likely be outfitted for extended cruising or living aboard).

If an 8 year old boat has 1600 hours on it, it has been used a fair bit. It could start to show signs of wear and tear if not maintained. Then again, it may have a number of improvements as the owner truly gets enjoyment out of it.

If an 8 year old boat has 5000 hours on it, it gets used a lot. You would really want to check into how well this boat was maintained.

If an 8 year old boat has 10K hours on the engine, that is a whole lot of motoring. The boat has likely been used pretty hard. The engine is likely ready for rebuild or replacement.

But as others have said, it really depends more on maintenance than hours.

An engine that was run for 20 hours / year, but never had the oil changed and was allowed to overheat for 20 minutes in year 7, is likely in much worse condition than an engine that was meticulously maintained and had 300 hours per year put on it.

Does this answer your question?

Ramblin Rod
About Sheen Marine

[spaman]

six years ago I bought a Beneteau 393 built 2001 in Greece (former charter yacht) which had 4500 hours on the clock. today the clock still shows 4500 hours (survey never revealed the gauge was not working) so actual hours impossible to tell. more importantly the engine still works perfectly and starts easily every time (so far/touch wood...). I have it serviced by Yanmar every year and will continue to do so.
long engine hours on an ex-charter boat is not unusual, but most of the charter companies are good on maintenance. it is unlikely that the rigging or other bits of kit will have been used and abused as much, but a survey should reveal any other defects.
good luck

[SkiprJohn]

Originally Posted by sunxpert

Ok, guys. Thanks a lot.
Probably not worth judging a sailboat general condition based no engine hours.

That's right! Some sailors just use their engines coming in and going out of a slip or anchorage so the boat may get used a great deal and have just a few engine hours indicated. For sailing vessels it is not a good indication of use.

Welcome to the forum of many answers. Some answers might even pertain to the question.

[Hoosiersailor]

Lots of discussion about comparing boat diesels to cars but I'm not sure that's a great comparison. In most cases a car will be towed to the junk yard before the engine gives out. It's pretty rare to hear about anyone having an oil related failure in a car anymore. Don't get me wrong, it happens but it isn't very common.

I just bought a new Ford F150 with the V8 last year. When I picked it up we talked about scheduling the first oil change and the salesman told me that it has an oil monitoring system and the light will come on to tell me to change it. ok... So I got to 5000 miles, no light...6000...7000...finally I got to 8000 when I started researching it and sure enough he was correct. The owners manual stated the same thing but not to exceed 10,000 miles. About 9600 miles the light finally came on.

I know new oils are extremely good but that seems extreme. Seems like only yesterday the recommendation was to change it every 3000 miles or 3 months. But when I think about it, do I really know of anyone that has had an oil related engine failure? I guess not.

[a64pilot]

Modern gas engine automobiles run extremely clean, a lot of it has to do with getting rid of the lead, spark plugs will easily go 100,000 miles now, I changed my Prius plugs at 125,000 and they still looked good, that wasn't possible with leaded gas.
GM was first with the oil monitoring system, called GMOLS, and it is brilliant, most other cars do not actually have an algorithm like GM does, it's just a light that goes on every X number of miles, 2010 Prius for example is 5,000 miles

So your right, you really can't draw too many conclusions comparing to cars, similar, but not the same.

[sunxpert]

Originally Posted by spaman

six years ago I bought a Beneteau 393 built 2001 in Greece (former charter yacht) which had 4500 hours on the clock. today the clock still shows 4500 hours (survey never revealed the gauge was not working) so actual hours impossible to tell. more importantly the engine still works perfectly and starts easily every time (so far/touch wood...). I have it serviced by Yanmar every year and will continue to do so.
long engine hours on an ex-charter boat is not unusual, but most of the charter companies are good on maintenance. it is unlikely that the rigging or other bits of kit will have been used and abused as much, but a survey should reveal any other defects.
good luck

Can you go a bit more into the survey and buying process? That's interesting.

[SkiprJohn]

Just a quick answer but for a larger more expensive boat a marine survey is pretty much necessary. Some surveyors won't do engines but will survey the rest of the boat. It's kind of like a home inspection when you are buying a house. They go through system by system and let you know what is wrong. Whatever they find you can ask the seller to correct before finalizing the purchase. The other option is that you can ask the seller to discount the price enough to make repairs yourself.

First you make an offer and make it contingent on good results of a marine survey. That way if the survey is bad you can back out of the contract. Depending on where and who you are making the offer to you may not have your earnest money returned. Boat brokers can explain that to you.

The buyer pays for the survey and they do not come cheap but can save you much expense and heartache in the future. If the survey points out problems don't ignore them, don't gloss over them and pay close attention. Sometimes folks fall in love with a boat and let their heart overrun their head and don't listen to the surveyor.

Good luck in whatever you find.