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Engine hours

Discussion in 'Big Boats' started by jwieneck, Feb 10, 2019. Add this thread to a FAQ

  1. jwieneck


    Joined Jun 3, 2004
    241 posts, 0 likes
    Hunter 41 DS
    US Punta Gorda, Fl
    I would like to get some thoughts on engine hours. So a Yanmar 55 hr that has 3,600 engine hours, oil changed each 100 hrs, injectors service at 2,200, Value serviced at 2,400, etc. Engine fires right up, no smoke, no excessive oil burn, no discharge in engine room ext. Dose this engine have to many hours? Boat is a 2005.

    When do engine ours become a concern? I have talked to two Yanmar certified dealers and one general machanic. They say it depends on neglect, Diesel engines develop corrosion when they are not run much and are not run hard. I have another dealer that says you have to rebuild the engine at 5,000 hours period. Then a four dealer tells me the 5,000 rebuild thing is for high performance Yanmar like you fine in big power boats. So what do ya’ll think?

  2. Tom J

    Tom J

    Joined Sep 30, 2008
    1,290 posts, 209 likes
    Catalina 310
    US Quincy, MA
    Sounds like you have had good advice. The engine has had good maintenance and is in good condition. Run it the way that is suggested, and you should be good. My Universal had 19 hours on it when I bought the boat. I continued to break it in as the manual described, and occasionally ran it hard, with almost no idle time. At 1500 hours, I pulled the mixing elbow and there was no carbon buildup.

    stuartsw likes this.
  3. stuartsw


    Joined Sep 22, 2009
    81 posts, 9 likes
    Hunter 36
    US Seattle, WA
    No, the boat does not have too many hours. Let's also remember that we're dealing with (what is supposed to be) an auxiliary power source. Our H36 is a 2009, and we have 1500 hours on her, and now that we live aboard, we cruise her a LOT. Thirty-Six Hundred hours sounds about right. My mechanic tells me that these Yanmars are good for 20,000 hours at least, properly maintained. Keep up the recommended maintenance, and-- do pull and check the exhaust elbow, if it has NOT been replaced already.

    Tom J likes this.
  4. Gunni


    Joined Mar 16, 2010
    5,768 posts, 1,399 likes
    Beneteau 411 Oceanis
    US Annapolis
    I have seen charter boat Yanmars with 4,000hrs that were absolutely ragged out and in need of replacement. My Yanmar mechanic claims to have seen Yanmars with 30,000 hours. My marina neighbor has a Yanmar with 10,000 hours. Charter boat engines are run for hours at idle, considered extreme use.

    If you only put 50 hours on an engine, but stick to a 100 hour lube oil change frequency you are changing the oil every other year, not acceptable. In addition to hours, Yanmar specifies calendar-based change frequencies for all maintenance. Coolant needs to be changed regularly to remove corrosives from the fresh water system and potential corrosion. It needs to be a coolant spec’d to protect against cavitation erosion of the Yanmar thin-cylinder wall design. Most of the Yanmar’s run a friction clutch transmission that depends on precise mix of fresh ATF additives. They also wear quickly when abused by charter duty and ignorant owners. Improperly pitched and maintained propellers can ruin an engine is short order. Yanmar has specific instructions about engine run speeds and use that are designed to meet their reputation for long life.

    Any engine that is run in overheat mode will live a short life. Any engine that is run in under heat mode will carbon up and run poorly and eventually run hot. All of these conditions can be addressed and not clearly evident to a new owner, so you need to do your research.

    If I were buying a boat with 3,500 out of charter I would assume a repower was needed and would negotiate that in purchase. If I were buying a boat with 3,500 hours from the original owner with well documented maintenance procedures I would have the engine inspected and run by a Yanmar mechanic (mine, not his) and perhaps accept that there was lots of life left on the engine. I fully expect to see 10,000 hours on my 4JH3E engine.

    Will Gilmore likes this.
  5. leo310


    Joined Dec 15, 2006
    129 posts, 45 likes
    Catalina Catlina 310
    CA Campbell River BC
    Another way to look at Hr to overhaul is when have you done it on your car, you put on over 1000 hr each year so if your car is 2005 then you would have over 14000 hr.

  6. Stu Jackson

    Stu Jackson

    Joined Feb 26, 2004
    20,258 posts, 780 likes
    Catalina 34
    224 CA Maple Bay, BC, Canada
    3600/(2019-2005) = 3600/14 = 258.

    General consensus of average engine hours for recreational use on multiple boating forums over the last 20 years I have been participating online is anywhere from 100 to 200 hours.

    257 is just fine.

    Sounds well cared for.

    The various input you're getting about 5K hours is absolute nonsense. Well cared for and operated diesel engines should last well over 20,000 hours. Diesel trucks and tractors (which these engines use) go far longer.

    In fact, some of the service you've had done on that engine is more than many have done for theirs with far more hours still going strong.

    I have 3600 hours on my 1986 boat. Bought it in 1998 with 888 hours in San Francisco, sailed there for 18 years and sailed (motored) up the coast in 2016 to British Columbia. That six week trip (one week harbor-bound due to wind) used 165 hours. My average? = 3600/32 = 113. But in SF I SAILED most of the time. Here, I motor most of the time. My trawler with a stick! :) But because of this little thing called winter, I only can go boating half of the time I used to in California, the distances are twice that here from those down there, so I average pretty much the same amount of yearly hours.

    Good luck, sounds like a winner. :)

    Will Gilmore and TomY like this.
  7. Paul Cossman

    Paul Cossman

    Joined Jul 25, 2004
    326 posts, 16 likes
    Hunter 42
    US currently in New Zealand
    I agree with Stu. I have 6700 hours on my Yanmar 4JH2-TE (1991 Hunter Passage 42). I'm religious about maintenance. Runs great. I asked my "local" Yanmar certified shop mechanic about hours and he told me they do not find it unusual to see 4JH2-TE models that have been properly maintained to be running perfectly at 10,000 hours. With one exception my injector jet nozzles have never even required replacement upon inspection and testing. I once replaced my mixing elbow and found it to be unnecessary and a wasted expense. We all know that it is better to have a good load on a diesel, but I'm not sure that concern is overstated. MUCH of my diesel use has been transoceanic or island-to-island cruising (most of my 50K miles), and for fuel conservation purposes I almost always run at 2K RPM down to 1500 RPM. When I took it down to the head to check out the carbon buildup, it was virtually nonexistent--just "dirty." Still runs like a charm.

    Tom J and TomY like this.
  8. Jerry Clark H356 SV Persi

    Jerry Clark H356 SV Persi

    Joined Mar 3, 2003
    646 posts, 51 likes
    Hunter 356
    US Grand Rivers
    I have a 2003 Hunter 356 with Yanmar 3GM30F with 1404 hours and 3563 on my Northern Lights 5KW generator. I service regularly. Did injectors and valve adjustments on the Yanmar at 1080 and Northern Lights at 2684. I haven’t done the exhaust elbow since primarily in fresh water except for Florida cruise in 2103-14. Refurbished my Maxprop at 1272 and changed out cutlass bearing at the same time. I’ve heard 10000 hours common for both my engines if maintained correctly.

  9. Capt Robbie

    Capt Robbie

    Joined Jan 24, 2017
    319 posts, 111 likes
    Hunter 34
    Us Red Bank NJ
    Hello Jwieneck
    I have a H34 1983. Original owner. I have done all regular maintenance sence day one. I have no hrs meter so I can only estimate my hrs to be about 4K plus which is a very low estimate.
    Everyone I have spoken to say that it's all about regular matinance.
    If you take proper care of a deisel engine they will take care of you.
    My deisel service tech along were other trade professionals I talk to all say deisel's can run for many thousands of hrs, without any major service over hauls. They say keep them properly lubricated and they will basicly run forever.
    A good example is Truck drivers, they put hundreds of thousands of miles on there rigs before major engine over hauls and they push them much harder then a sailboat ever can.
    As people have said to me, a deisel engine is just starting to get broken in at 8k - 10k. I am fanatical with maintenance on my engine, change oil every season , filters , belts, etc. I have not had any major breakdowns mainly due to preventive maintenance.
    Deisel engines are built to last for years, and as long as you don't
    Abuse it and maintain it, yours should serve you well for manny years.

    Hope this helps

  10. Secret sail

    Secret sail

    Joined Feb 23, 2018
    15 posts, 2 likes
    Hunter 356
    Secret Fr Marseille
    In europe Yanmar is distributed by Fenwick... The guys that make industrial elevateurs fork lifts etc. Fenwick say a major engine rebuild only after 15000 hours. Knowing that I think these boat engines are really good. There are more problems with peripheral equipment (water pump, heat exchanger and elbow) than the actual engine. I do 500+ hours per season, Oil change regularly every 150 hours with good brand name oil. I clean the heat exchanger in 'ultrasons' every 3 years or so. Keep an eye on the elbow and everything should be fine.
    The quality of diesel is very important too. I add 3% 2 stroke oil in my diesel for lubrifying purposes. It just adds what the anti pollution laws took out of the diesel circa 2000 :) Silent start ups and less clacking!

  11. Maine Sail

    Maine Sail Moderator

    Joined Feb 6, 1998
    10,824 posts, 633 likes
    Canadian Sailcraft 36T
    US Casco Bay, ME
    I'll take the 3000 hour 20 year old well maintained engine over the 200 hour 20 year old poorly maintained engine every day of the week. I have numerous customers out there with 8k - 14k + hours and some commeccial fishemen with over 20,000 hours with no re-builds.

    I have posted this before but here it is again...

    My buddy Darren owns a good sized excavating, irrigation and landscaping company in Colorado and we talk diesels quite a bit. He has a good sized fleet of diesel equipment and a couple of them have over 20k hours with no rebuilds. The last time I spoke with him about engine longevity he had one Yanmar block and one Mitsubishi block with over 20k hours. He bought both of these machines used with about 5k hours on them back in the late 90's. Neither engine has needed a rebuild and these are the identical industrial engine blocks to the ones we use in marine applications..

    Most of his smaller engines are either Yanmar or Kubota but he does have a few Mitsubishi's too. His engines run all day and basically never shut off. They idle for long, long, long hours. Now granted these are not in a marine application but in well over 500,000 hours of combined run time on his fleet he has yet to rebuild an single small diesel engine. All his machines run Shell Rotella (not synthetic) and it gets changed regularly. Of course he buys his oil in 55 gal drums and I buy it by the gallon...

    If heavy equipment running Yanmar, Mitsubishi and Kubota blocks can rack up10k to 20k hours, while doing hundreds and hundreds of hours of idling per year, with no rebuilds, then a well maintained marine diesel can do the same. Our Westerbeke is well over 4000 hours and much of this is engine driven refrigeration hours.

    When we had the discussion about not letting diesels idle a few years ago he just laughed about the glazing the cylinder walls. His sarcastic comment was something like "Sh&t I better let my guys know not to let them idle". Course he'd already been doing it for 20 some odd years, with no failed engines or rebuilds needed, so he was surprised to find out his engines were going to die soon from light loading.

    Our engine has idled perhaps half or more of its 4000+ hours. It burns zero oil, has cross hatching in the bores that looks like new and she purrs like a kitten. We have Sea Frost and often sail with the engine idling or will let it idle to chill the plate if we are alone and not disturbing others. Our boat also did a five year 24/7 on-the-hook almost circumnavigation. She had no generator and only the alt and a single solar panel. That racked up the majority of the current hours.

    This customers engine is still going strong today, no rebuilds, and this picture was taken in 2014..


    Tom J likes this.
  12. Gunni


    Joined Mar 16, 2010
    5,768 posts, 1,399 likes
    Beneteau 411 Oceanis
    US Annapolis
    The difference between a dirt diesel and a marine diesel is seawater, the heat exchanger and most specifically the seawater mixing elbow. Run a Diesel engine with a restricted heat exchanger or carbon plugged exhaust and it will not live a long and prosperous life. You will see this in boats brought out of the charter trades where despite regular maintenance schedules, and oil changes the engines have obviously been popped by heat. Every Yanmar owners manual I have ever read talks about blipping the throttle to rated max RPM after a session of prolonged idle to “remove carbon deposits”. They are designed as extreme duty high speed diesels. But every marine diesel lives under imminent threats of overheat that dirt diesels do not - noted in the first sentence above.

  13. Maine Sail

    Maine Sail Moderator

    Joined Feb 6, 1998
    10,824 posts, 633 likes
    Canadian Sailcraft 36T
    US Casco Bay, ME
    All diesels run a risk of overheating due to lack of maintenance dirt or marine. The key with any engine is that it is well maintained. Again, I will gladly pony up for the clean well maintained (with proof / service records) 3000+ hour marine diesel vs. the slopy ill maintained low hour engine every day of the week. I think far too many folks are overly concered about mileage/hours on motors when the real concerns should be about how has it been maintained. For example our engine gets:

    Oil changed twice per year (Rotella 15W-40 since new)
    Gear lube changed every oil change
    Magnet for gear oil drain plug
    Gear lube cooler was added (not stock)
    Has a remote oil filter that added 1 quart of capacity to the system and over 4X the filtration media
    Engine coolant is changed every season with Rotella ELC.
    When ever an engine part gets some rust or corrosion it is removed, bead blasted & re-painted
    Hoses inspected continually and replaced when ever needed
    Every hose clamp on the engine is non-perforated
    HX anode replaced twice yearly
    Air filter replaced bi-yearly
    Impeller replaced each year
    HX pressure tested bi-annually
    Valve lash checked / adjusted every 300 hours
    Injectors dropped at injector shop and tested /serviced every 500 hours.
    When the engine is run it is always allowed to run up to full temp before it is shut down
    The engine has a full gauge package (not the standard factory set up) not just idiot lights
    The fuel tank is 100% spotless and features an on-board fuel polishing system that keeps it that way
    We only run ValvTect fuel and only fill up at ValvTect dealers only (this is pretty easy to do in Maine)

    I fully expect this engine to outlast us and I would take this 4000+ hour engine every day of the week over most sub 500 hour engines. If an owner even did half of this list I would have little concern over an engine with high hours. Maintenace is most important.

  14. Don Lucas

    Don Lucas

    Joined Jan 12, 2011
    754 posts, 20 likes
    Hunter 410
    US full time cruiser
    Besides doing the correct maintenance (oil etc) I feel the biggest killer of boat engines is that they don't get run enough to fully warm up. Sailors seem to get all proud of themselves because they only run their engines for 10 minutes to "just get off the dock".

    Tom J likes this.