Diagnosing Low Power Output on a Northern Lights 12kW Generator (MV Dirona Channel)

In this installment of our maintenance series, we diagnose low engine power output on a Northern Lights 12kW generator. This engine is unable to produce more than 7kw of power, but can reliably deliver that, and otherwise is running fairly well. We walk through the diagnostic procedure checking for intake blockage, fuel system problems, exhaust restriction, exhaust design problems, and valve adjustment.
You can read more about our travels at mvdirona.com, including a live map with our current location.

[@nettech5]

James is THE most senior engineer in all of Amazon. And boy does it show in videos like this. His scope of expertise is simply huge and such a genuine nice guy as well.

[@garyengelman7867]

This is something I have never seen talked about in any of the classes I have been in. I have a FAA Airframe and power plant mechanic’s license and have been in alot of class’s. NICE job.

[@MVDirona]

Thanks for the feedback on the video.

[@lightning9279]

3400 views with many likes and no thumbs down. This must be a YT record. Well done you two.

[@MVDirona]

Thanks for the feedback on the video.

[@michaelrowse4917]

What a great video. I'm an advanced automotive engineer and have never seen such a clear explanation of problem identification. The two of you working together, the questions asked, the detailed replies all work beautifully. Many thanks guys!

[@MVDirona]

Thanks for the great feedback. Jennifer and I both appreciate it.

[@AgentRafa]

This is awesome. James I could watch you fixing engines all day long. Thank you so much for sharing.

[@MVDirona]

Thanks for the feedback -- much appreciated. The parts arrived Friday night so we changed the cylinder head over the weekend. The generator is now back to full output again.

[@robschaffer2189]

I always like your thorough diagnostic walk-through explanations. I have been a mechanic and hot rodder for nearly 40 years and was nodding and saying, "yep" to my screen for the better part of 40 minutes, lol. Still chasing my dream. I'll live vicariously through your adventures in the meantime! Thank you for sharing.

[@MVDirona]

That's nice of you to pass that on. We both appreciate the feedback. If you are interested, there is lots more on the trip on the web site: mvdirona.com.

[@TAllyn-qr3io]

When I was working at ADE, the smaller units (gen sets and propulsion) were built in Japan and shipped to ADE HQ in Seattle. Where it was tested in the test cell, QC’d, cleaned and prepped, crated for customer and shipped. It sucks that this happened to you guys 😕 memories of tight spaces in engine rooms for a tall guy…me 🤨

[@MVDirona]

We love Northern Lights products and would choose them again in a heartbeat. Our generator needing a valve job at just under 7,000 hours is arguably a bit early but the service and support from the ADE team is simply amazing. We're 100% happy.

[@adventureseeker9800]

This is fascinating stuff. Loads of fun listening to him explain this stuff. Reminds me of my high-school science teacher! Very cool guy.

[@MVDirona]

Thanks!

[@-zo8732]

great explanation. lots of knowledge and experience.

[@MVDirona]

Thanks for the feedback!

[@Erik-rp1hi]

Next video on this job will be for me tomorrow. Good clean explanation of the job ahead. I had to remove the heads on the small block Chevy powering my 280 Volvo Penta in/out board because of gasoline turning to gum/varnish. That made all the valves tough to move until one was so bad it pull the rocker stud out of the head. Hot tanked the heads replace the stud and was good to go. 30 ft. Bayliner, twin engine with big access doors outside. Some crawling but was ok. Replacing the crank seal is a bigger job I bet.

[@MVDirona]

Swapping heads on a small block in a 30' boat won't be leaving you a ton of space work. Glad it went well. On the rear main oil seal, you are right it'll be a bigger job but, so far, I've been lucky. It's just about stopped leaking. My theory is the dead #3 cylinder wasn't firing but was getting fuel prior to me changing the head. I think we likely had fuel diluted oil and it was far more prone to leaking. With the head change and an oil change, the rear main oil leak is just about gone. I fully expect it to return but it's been 1,279 hours since the head change and the seal is still looking great. Thanks for the feedback on the videos.

[@ronaldbarrett4386]

Excellent technical knowledge, you usually get it right the first time with your approach .

[@MVDirona]

Thanks for the feedback on the video.

[@renerichter7296]

This is impressive technical knowledge!

[@parlimage5050]

Really like your logic and explanation. Bravo! 👍

[@MVDirona]

Thanks!

[@Eric-mm6wo]

Awesome. Step by step all problems can be happened and taught us the entire solutions. You're encouraging us we can handle Nordhavn 50 sooner future. Thanks

[@MVDirona]

If you are patient and willing to learn, it's very doable. The work required goes up and down over time but, if you stay ahead of it, you have a lot of flexibility on when you do the work and it won't disrupt or in change your plans. Good luck on your plans to get a Nordhavn 50. We have found a Nordhavn to be a great adventure platform.

[@Topsniper2142]

Jennifer peppering questions in at James was great! I had some of the same questions.

[@MVDirona]

I agree it does help because I often get focused on the job and will forget to describe what I'm doing or why a step is advised or don't explain something in sufficient detail. Thanks for the feedback.

[@100pyatt]

I'd highly Recommend with your 1000hr maintenance to run Amsoil Diesel Injector cleaner concentrate through your fuel injectors to keep them spraying consistently. It's one of the most powerful and quickly effective diesel injector cleaners I've ever used. Worth the money 100%. I just sold a semi truck with 18,000+ hrs on the engine, original injectors and common rail. It got Amsoil injector cleaner every 30-35k mile PM

[@MVDirona]

I've heard good things about Amsoil and other fuel additives from enough good people that I know there are good reasons to use them. But, thus far, I've elected to run on good quality diesel that hasn't been in the tanks long and it's been giving fairly good results.

[@daviddiana8354]

Great explanation of the process to identify the problem.

[@MVDirona]

Thanks for the feedback on the video.

[@darz3]

Having undertaken a cylinder head gasket change on a single cylinder engine, I found the diagnosis and plan to resolve the problem very interesting

[@MVDirona]

Thanks for the feedback. We changed the head over the weekend and will post that video when it's ready. It's great to see that engine back to running at full power.

[@TonyMoller]

Hello Jennifer and James, I just need to say a big thank you for sharing your knowledge and so much from your different experiences from your travels. Not only here on KZbin, but on your website mvdirona.com as well. As a true Nordhavn dreamer myself, I can truly say that your channel is one of the most enjoyable and that in so many different ways too. And for me one thing that stands out is how kind and decent you come across in the videos. So I hope you too find it rewarding enough to continue to post videos, and know that it’s so appreciated. Wish you safe travels, fair winds and following seas, from one of your Norwegian followers👋🏻.

[@MVDirona]

Thanks for all the kind words. Both Jennifer and I appreciate it. And, if the Norwegian borders open soon, we plan to again set course your way to enjoy one of our favorite boating destinations.

[@slochmiller]

Enjoy your videos. Thank you for sharing.

[@MVDirona]

Thanks for the feedback on the videos.

[@niko-zs6vv]

GOOD DIAGNOSTICS ! THANK YOU FOR SHARING THIS NICE VIDEO, I LEARNT SO MANY.

[@MVDirona]

Thanks for the comment. The next video we post will be replacing the cylinder head on that engine, investigating the cause of the problem and looking for any related problems.

[@niko-zs6vv]

@@MVDirona mmm, I look forward to watch it, thank you for answer.

[@BaronWeber1]

Your explanations are extremely educational for me, and enjoyable at the same time. Thank you very much for the video, thumbs way up from me.

[@MVDirona]

Thanks for both of us. We appreciate the feedback.

[@Helmut_aus_N]

watching every of your videos here in Germany. Love Nordhavns. I'm very surprised hearing you say: "it's not a lot of work", an than understandig that you are going to disassemble a whole Diesel-Engine und put it back to life again. If I would do this, the engine probably would be wrecked :-) You're really great people.

[@MVDirona]

Thanks for the comment on the video. As of this weekend, we are no longer forced to speculate on how long the cylinder replacement job will take. We did it over the weekend and it's bit more than a full work day and it probably should have been done in a single day. So it's big in that the entire top half of the engine needs to come apart but it's still not that bad if you look at the total time required to do the job. The generator is now back to running at full power and it sounds smoother perhaps because we changed the fuel injectors at the same time.

[@ryanconrad9811]

Fantastic video, you both make a great team.

[@MVDirona]

Thanks for Jennifer and I.

[@ronwalker5856]

Excellent explanations thank you and stay safe.

[@MVDirona]

Thanks for the feedback on the video.

[@classicraceruk1337]

What a fantastic video very in depth and informative. Hope you show the rest of the work. As an aside I used to race ( grass track) in the 70’s using used Norton Dominator 99 engines they were cheap. Problem was once they had been tuned and running on methanol the bolts connecting the big end caps to the crankshaft stretched and boom no engine!!! The same thing as a valve stretch, we changed the engine to a better one eventually.

[@MVDirona]

I know what you mean about seeing the odd race engine let go. One year we were racing Alfa Romeo and experimenting with how high we could rev those relatively long stroke engines. Learning about that consumed several quite nice engines. Thanks for the feedback on the video.

[@classicraceruk1337]

MV Dirona That brought back memories racing is fun when you can afford it’s associated costs. I loved it. Thanks again for the great video today.

[@MVDirona]

I had meant to say "long stroke engines" and, yes, you are right about racing is fun if you can afford. My involvement was mostly working on other peoples equipment so less exciting but more affordable :-).

[@chainsawsandgenerators9952]

i'd hold off on doing that rear main seal. from my experience generators will leak a little just after the engine has stopped, from the crank dropping off the film of oil, deforming the seal and letting a little oil drip from the top side of the seal. and yes, i love a spotless engine room too.

[@MVDirona]

You are right, the generator has gone more than a thousand hours since the head was replaced and the rear mail oil leak just about completely gone away. The only two changes that were made were: 1) the cylinder head was changed and 2) I changed the crankcase ventilation system to run slightly negative pressure rather than slightly positive. I believe the cylinder head change is what made the difference. Cylinder #3 had a bad exhaust valve seat causing #3 to not reliably fire and fuel to run down the bore diluting the engine oil. Once back to peak operating condition, it leaked no further oil.

[@captainrick9379]

Keep us posted! And Thanks for sharing!

[@MVDirona]

Thanks and, as you guessed, there will be a part two. The parts arrived last Friday night and we put the new cylinder head on over the weekend. The old head was in really tough shape but the generator is back to full output and it sounds great.

[@johnwood2596]

A ton of work so much Reward Super Job!!

[@MVDirona]

Thanks for the comment. We did the change of the cylinder head over the weekend and it's now back to running well with full power output.

[@reighbh13]

As always a brilliant video that a comparative idiot like me had a good understanding of what was explained. Cant wait for the fix video.

[@MVDirona]

Sometimes I wonder if the videos are more work to produce than the actual projects they document :-). But we are working on it and appreciate the feedback.

[@reighbh13]

@@MVDirona Its very much appreciated though.

[@zoomcctv]

Love the videos, interesting and educational at the same time. Will you ever make a video detailing your control system ?

[@MVDirona]

That's a really good idea. I hadn't thought of it but I think we should do it. Not sure when but, yes, we'll almost certainly do it. Thanks for the suggestion.

[@rpwsalina]

Love your video's ! What about "AT-205 RE-SEAL" to soften and rejuvenate your crankshaft seal ? This would save you a lot of work removing the seal for now…. Watching from the Netherlands.

[@MVDirona]

Thanks for the feedback on the videos and the pointer to the oil additive. I chose not to use these additive partly because I worry about side effects where non-leaking components start to leak or temporary corrections where the softened lip seal is better for a while and then a few months later gets worse fast. These may be unfounded worries but the car and engine manufacturers have fairly big warranty costs caused by oil leaks and, even though they like to avoid unnecessary costs, they replace seals rather than leaning on additives. I would think if the additives where a good long lasting repair, the manufacturers would save money and use them. Given they chose not to use them and recommend against using them, I'm not comfortable using them myself even though the thought of an easy solution is quite appealing :-). Thanks for the suggestion.

[@rpwsalina]

@@MVDirona The best thing is always to replace and use oem-parts when you do, you're right ! These additives could in my opinion only buy you time towards the actual repair. Again keep sharing your video's !

[@MVDirona]

That makes sense. I do plan to wait a bit on the rear main oil seal. It's a bit of an experiment where I vent the crankcase to atmosphere rather than run slightly positive pressure. I had started that experiment just before the valve problem interrupted things. I'll go back to it and, if we are lucky, we can defer the rear main oil seal for a few more months.

[@JamesCoffeeStudios]

Three things: 1) Thanks for this video. Very informative and well done. Good job. 2) I hope that you do a video of the actual head replacement. 3) Is your new cylinder head assembly white? Or do you paint? Or do you simply end up with a two-color engine? Thanks so much for your time and effort to make these videos.

[@MVDirona]

Thanks for the feedback. We will do a video of the cylinder head replacement. In fact, the parts arrived last Friday night so we did the cylinder head change over the weekend and we did a post mortem on the old head to get an understanding of what caused this failure. The details are posted to mvdirona.com and we did video the work but it'll take some time to get an 8 hour job down to something reasonable from a video length perspective but we do have some time on our hands so we should be able to get that posted over the next couple of weeks. That's a great question on the cylinder head not being painted. Every time I put a new part on the three engines in Dirona, it's unpainted. In some ways, I don't like that but, in others, it's an interesting way to document what has been done. Still on a cylinder head, it won't look great and it will rust I figured I would need to do something. I was really surprised Friday night when the new parts arrived to see the cylinder head came painted. Yeah!!!! Not what I expected but really appreciated. Thank you Northern Lights!

[@barrysummers1622]

Well guys, that is my 4th time of watching this Video, very very interesting, thank you again, keep them coming.

[@MVDirona]

Thanks. We have 238 hours on the new head and it's running well. And, for some weird reason, the rear main oil seal hasn't leaked a drop in 69 hours. I'm sure it'll be back but it's nice to have that problem off the "needs to be done soon" list.

[@williamjordan811]

Great teching Method, Very Good Conceptual Explanation of all the Fluid Flows and Heat Exchange concepts. My favorite Term "Failure Modes." Being an Ex-Navy Nuclear Reactor Operator, I Haven't considered Marine Diesel Technology very much, as most generation of Power is accomplished through using steam turbines, and condensate heat exchangers in closed loop systems. Of coarse control systems were/are similar to your installation I guess, because I'm not familiar with Your setup, where we used Programmable Logic Controllers as well as mechanical controllers for Systems Integration and Control. Now I have a clue as to what's going on...Thanks skål!

[@MVDirona]

Your control systems were considerably more mission critical since you were taking care of a nuclear reactor. Mine are far simpler being responsible to start and stop the generator, do electrical load shedding/peak shaving, track all sensors, set audible alarms, indicators, update displays, send email, update data on mvdirona.com, chose the best wide area network connection among 5 WANs (cellular options and satelite connections). There are 5 Raspberry Pis (small Linux computer) spread around the boat doing digital input, digital output, and some analog input. A central system interfaces with the 5 Raspberry Pis sending actuator requests and collecting sensor input which is written to a central database. This program also reads and writes to the NMEA2000 bus and sends and receives data from it as well. Most decisions, all alerting, alarming, and reporting and done by the central system. Not quite as life critical as maintaining a nuclear power plant but still useful :-).

[@williamjordan811]

@@MVDirona Thank You, Yes Redundancy and Fail Safe are the Watch Words in the Nuclear Industry. I love the Raspberry Pis< I've used them in many projects from Ham Radio to building control systems in my Motor Home, great for builder Projects. Thanks For the glimpse into Your Control System, I'm sort of A geek for Grabbing the Tech Manuals For a Good read Before grabbing a Fictional Novel, I just love the facet of system integration and putting the pieces together to create an "orchestra!" Such fun! Again Thanks and skål!

[@MVDirona]

I agree with you. They Raspberry Pis are amazing. You can have 28 pins of general purpose I/O, a full Linux computer, with adequate storage for under $50 without needing to buy in volume. It's amazing what can be done these days almost for free if you are OK with writing a few lines of code. We probably should do a video someday on the control systems on Dirona. It all surprisingly simple and yet the system works really well.

[@williamjordan811]

@@MVDirona I Would Love That!

[@James-seafan]

interesting video

[@MVDirona]

Glad you think so!

[@BenDoverII]

Great content, very informative...And that occasional low key humor.

[@MVDirona]

Thanks for the feedback!

[@Dan-sd5bm]

Very Helpful

[@MVDirona]

Thanks!

[@fryfrysk]

Curious to see if the failing valve seat is indeed the cause . Compliments for a thorough step by step ( and very understandable) diagnosis : good preperation is half the battle !

[@MVDirona]

Thanks for the feedback on the video. Over the weekend, we took the head off and the #3 exhaust valve is so bad you can see the problem from a yard away. Check out this picture: mvdirona.com/trips/med2020/med3.html?bleat=6%2F20%2F2020%3A+Valve+High. It's back to running well again and we'll post the cylinder head change video as soon as we can.

[@fryfrysk]

@@MVDirona Indeed the most probable cause as well a good lesson to run the generator more frequently espcially after rough crossings . But all well that ends well : a great job ! Glad you like Scotland and Ireland(Kinsale) : both

[@fryfrysk]

...my favourite european countries as well as Denmark and Finland

[@MVDirona]

We like both Finland and Denmark and spent a lot of time at each last year. For this summer, we were originally think of the Med but gave up on that because of COVID-19. We're now leaning towards Norway depending upon when countries open up.

[@R2robot]

"Running the rack" (adjusting valves) on diesel engines used to be one of my favorite tasks at my family's diesel repair shop. But I think it was less stressful working on other peoples stuff. It's never fun to have your own engine components fail. Also, where is your furry supervisor/project manager?

[@MVDirona]

Your right, it's not ideal to have an important component like the generator off line. The parts arrived Friday night so we changed the cylinder head and the engine is now running well again. the valve seat on #3 exhaust was a mess and none of the valves were in great shape. But it's all back running now. That'a good point on the furry project manager. Spitfire normally does show up to check on the quality of the work and make sure nobody is slacking off but seems to have slept through this one. He did show up several times while we were changing the cylinder head though.

[@matthewcrocker7261]

@@MVDirona #3 exhaust was a mess meaning you had water back feed the exhaust? Could that of happened during severe weather? Or, is there another potential problem?

[@MVDirona]

We'll get into more detail in the next video but it does looked like there has been water in there in the distant past. As a consequence of investigating the exhaust design and operation, we know that there is not excessive amounts of water collecting in the muffler when the engine shuts down. I don't think water can get in under normal operation. But there does seem to be evidence of water. My hypothesis is during the 4 or 5 really rough water experiences we have had in the boat, water did get in due to extreme boat heel, some water splashed in from the remaining water in the muffler. Here'e an extreme example from when we were in Australia and the boat was knocked over to 69 degrees: mvdirona.com/2014/09/69-1-degrees/. Another is the rough water we saw on the North Atlantic Crossing in 2017: kzbin.info/www/bejne/naaon4emZ8ZpicU. During these events the boat was leaned over a long way and water could have got in. I suspect largely nuisance amounts and if the generator had been run after those events, thing would be fine. But, instead, we didn't use it for many days and sometimes weeks. The lesson for us is to fully exercise all mechanical systems after the boat has seen extreme conditions.

[@bllzdp6558]

@@MVDirona the proximity of the water injection to the valves is suspect. many manufacturers have issues with this and fail to recognize it, please see sbmar.com for good information along with great illustrations on how to remedy. At the very least it's a great read.Best wishes and really enjoy your videos.

[@MVDirona]

It's good to hear from the Seaboard Marine team. Thanks for passing on your experience with wet exhaust systems my way and please say hi to Tony for me.

[@colinhawkins6853]

Another very informative video. It's really interesting to hear how you diagnose the problem. Where did the new head come from?

[@MVDirona]

The new head came indirectly from the manufacturer, Northern Lights, via one of our favorite marine retailers in the US. It was sent here by UPS air freight which is a bit expensive but we already had reasons to do an air freight shipment. I needed to get a used power takeoff clutch for the wing engine shipped over here as well so the two parts essentially "shared" the shipping costs so it wasn't too bad. And, the good news, is the generator is now back to fully operational form.

[@theresnobodyhere5778]

that was a great explanation of wet exhaust system,its only when you get the head off do you get the bigger picture whats happening,i v seen valve seats split cracked ,loose carbon building up underneath causing them to sit lop sided that but those problems do the opposite make clearance enlarge on the rocker and loose compression ,i see you got the job done reading comments,sounds like injectors were loosing atomisation and running rich fuel saturation that destroys exhaust valves and partial burning of fuel excess goes down through piston ring gaps and mixes in sump oil, check old engine oil will smell of diesel ahhh could that perish crank seal which is a rubber / plastic mix composite material not deisel resistant ?

[@MVDirona]

Good set of thoughts. There is no indication of diesel oil dilution. Oil level doesn't rise, there is no aroma of diesel off the old oil, when dripped onto a paper towel, lighter diesel elements don't migrate away from the engine oil. I'm pretty sure we don't have that problem but, since we do have 6,700 hours on the injectors I did change them. So, if there is any issue there, it should be addressed by installing 3 new injectors. Any oil seal is oil resistant of course and, diesel is just a very light oil, so I wouldn't think there would be any impact on the rubber if there was diesel in the sump. The crankcase vent connects the crankcase with the intake manifold right near number 2 intake valve. The valves appeared to be leaking based upon the valve face not being polished. If the intake was leaking especially #2 intake, it could cause pressure spikes in the intake and, as a consequence, in the crank case. I suspect the mostly likely answer is the oil seal fail since many have had the same problem but so interested to see if it's different with properly sealing valves that rather than change the rear main oil seal, I'm holding back to see if it's leaking less with the new valves and seats. I suspect I'll have to change it no matter what but I would like to see if there is anything to learn first.

[@theresnobodyhere5778]

@@MVDirona yehh it would send pressure back to crank blow the seal,was good temp fix to remove filler cap give a relief of pressure, but usually when a gasket or seal gets a track across it to create a leak its prone to always leak but you could be lucky and reduced crank pressure now and the new head and injectors it,ll be running sweet should see difference in feul burn cost

[@MVDirona]

I think you are right that once a leak starts its very likely to continue. I'm just about positive I'm going to have to replace the rear main oil seal. But the engineer in me can't resist the experiment of running it for 30 to 50 hours to see if the oil leak is much reduced. I'm mostly just after testing the theory that the leak may have been caused by leaking intake valves.

[@blindekuh8891]

Well yes, it's very impressive. And also a great video with understandable knowledge bits. So let me ask the question: How did you manage to collect all that knowledge? Following your channel, it's not only about diesel engines - you know everything. Did it just come along form your former life 'as some kind of genius'? Or did you learn all those topics just to operate MV Dirona? Or do you have good advice from the manufacturer? Please let us konw (the ones that would never cross an ocean without those skills :-).

[@MVDirona]

A little bit of all those options. Many years ago I was a professional mechanic first at a Chevrolet dealer and later at an Alfa Romeo dealer. I've never worked professionally on diesels and it's been nearly 35 years since I worked on card professionally but it's a useful background when it comes to taking care of a boat. The manufactures who supplied equipment on Dirona are incredibly helpful as well. It's been a decade but if I call or email Northern Lights (Wing engine and Generator), ABT/Trac (hydraulics and stabilizers), Cascade Machinery (John Deere distributor), or Pacific Asian Enterprises (Nordhavn), they are all super helpful. The collective commitment of all these manufactures to the success use of their products is incredibly unusual and a big part of what makes a Nordhavn special. And, of course, if you are patient and careful, none of this is rocket science. Anyone who can approach problems methodically and thoughtfully can take care of ocean going boat. And, more importantly, with good redundancy, and Nordhavn's do usually have good redundancy, they should just about always be able to complete a trip and be professionally serviced at the next port.

[@blindekuh8891]

@@MVDirona .. and still very impressed, but on a much higher level now. I'm used to take care of a 50+ years old vessel. So, I fully agree with your statement about 'patience and care' - however, it gets more complicated when it comes to spare parts and advice, when there are no manufacturers available any more. Thank you for your answer and ongoing inspiration through this channel, this is very valuable!

[@MVDirona]

Taking care of a 50 year old vessel is harder for many reasons but a key reason is parts availability. You end up having to replace entire components with new ones or make parts for old components which takes more time and more skill. Even on Dirona we will eventually have to face some issues with out-of-service parts. Are refrigerator and the garbage compactor are both no longer available in that form factor and for the fridge there is suitable replacement from any manufacturer. For the garbage compactor, there appears that there are replacements available but they are 240V/50hz appliances (thanks to a reader to point that last one out). When the parts aren't available, everything gets more difficult and requires more skill.

[@wb5plj]

Please film it and explain if you would. Nice to find out.

[@MVDirona]

Will do. The work is done and we're working on the video.

[@5400bowen]

Where did you get the repair manual? And have you done anything on the fuel pump? I have a unit that is leaking out of one of the connectors on the fuel pump to the injectors. Do you have any suggestions? I've talked to Northern Lights and they said there are only shims under the hex connectors.

[@MVDirona]

You'll find the manual here: www.northern-lights.com/technicalinformation/manuals/. I've not had any leaks or issues from the injection pump so can't offer you an experienced perspective on that one. I've heard they have a greater propensity to leak from that location when operating in excessive hot environments. Make sure the temperatures inside your enclosure are under 130F.

[@santiagoboggi1510]

Can by posible that the salt water in the manifold be caused cos the vacum produced in the manifold, just because the exaust valve had a leak? Sorry about my english, my native language is the spanish.

[@MVDirona]

I understand your thinking. One factor to keep in mind is a diesel (compression ignition) engine speed is controlled by injecting more or less fuel whereas a gasoline (compression ignition engine) has a throttle that restricts airflow into the engine. So it's common for gasoline engines to have fairly high intake manifold vacuum (pressures significantly less than atmospheric pressure). The only restrictions in a diesel engine intake is the slight restriction of the air filter and plumbing. So, generally diesel engines don't have strongly negative pressures in the intake manifold. But it will be slightly negative. In a correctly engineered installation without casting problems or serious corrosion, there is no way for sea water to get to the intake manifold. There is sea water injected into the exhaust and the only protection the engine has against sea water intrusion is the flow of the exhaust and gravity. The more I study this issue the more I see potential flaws in raw water exhaust systems that I was previously unaware of. However, they do work if properly designed. The risk situation is when the engine is off and the boat is heeled over unusually far or there is something wrong in the exhaust design or high wave pressure or extreme angle that causes excess water to accumulate in the muffler. This can be forced up into the engine. Its unlikely to happen when the engine is running due to pressure of the engine exhaust but, if the engine is off in extreme conditions, water intrusion can be a risk and that's my theory. I've posted a lot more detail here with pictures: mvdirona.com/2020/06/valve-seat-recession/,

[@santiagoboggi1510]

MV Dirona , looking at the photos, it seems that he is getting some water in the combustion chambers. probably for some reason some water from the exhaust is entering through the valves

[@MVDirona]

Here's some more detail on the issue with pictures: mvdirona.com/2020/06/valve-seat-recession/. Because the valves are corroded , it appears that they have seen water. Because the valves are corroded only in one spot rather than all the way around, it suggests the water intrusion only happened once on the logic that valves rotate in the head in normal operation and the corrosion should be all the way around if it happens frequently.

[@enuopower5567]

Very nice video! Just one question, how does the genset exhaust inside heated air? I don't think it will have a good ventilation inside the enclosure, just relying on the shutters, in the absence of exhaust fans. Most heated air from generator end will be trapped in the enclosure which cause generator end high temp. after running a few hours, voltage will rise. We've suffered such problem, I think at least one exhaust fan is need to help exhaust inside hot air.

[@MVDirona]

You're right that generator enclosures can be a source of engine temperature problems and thermal related faults. This particular enclosure design does flow air through it with fresh air brought in for the generator intake and, separately fresh air flows in the back (gen end) and forward to be exhausted out the back. Northern Lights appears to be using the flow from the generator end which has a integral centrifugal fan (most do) do drive air through the enclosure. I was skeptical and put a temp sensor in the enclosure and it never gets over 130F in the hottest climates we operated and is usually in the 120F to 130F range. The engine room itself runs a +30F deltaT so in 80F weather, the engine room will be 110F so maintaining under 130F is pretty impressive in my view. The most common fault mode is to lean things up against or pack things behind the enclosure that limit flow. Another common failure is the insulation inside the enclosure peeling free and blocking air flow. There is no question that the simplest and easy to maintain approach is to omit the enclosure.

[@enuopower5567]

​@@MVDirona That is an air dam, which directs all fresh cool air into back end of the generator and also prevents the recirculation of heated air from the engine and generator end, this is a common design for most genny brands. 120F to 130F inside of enclosure should be a normal indicator, very curious how NL can make it, especially an air duct (for noise reduction) is also designed at the air outlet, but this will greatly increase the exhaust resistance! We had a 15kW Kohler before, similar air inlet and outlet design like NL, enclosure temperature can reach at 150F to 165F, especially at full loads we tested, which make generator end surface temp. reach at nearly 230F, cause high voltage alarm. Only find Phasor has designed an exhaust fan on the top, NL, Onan, Kohler, Westerbeke all don't have such fan, very very weird how can they solve the inside high temperature problem, the only reason we can explain is maybe the large capacity fan between the engine's flywheel and the generator. Even so, I still think they can't run AT FULL LOAD for a long time(no more than 2-3 hours), maybe 70% - 80% genny rated power should be no problem, this may also be the original intention of these genny brands, thinking that users will not run at full load, or even if you run at full load, you will not use it for a long time. How many kilowatts is the load, when you measure the temp? Thanks!

[@MVDirona]

Yikes, 150F to 165F is high. Your idea of putting in an active (powered) fan is a good one. The simple solution is to remove the cover -- many Northern Lights operators elect to take that route. We have a large amount of charger capacity so we can max out the gen and it'll run at 85% load for 4+ hours without problem with enclosure temp staying

[@enuopower5567]

@@MVDirona What you said is absolutely correct, most users will not use the genny at 100% full load, and when using it, the doors are removed. Maybe these brands have also grasped this point. But they should mark that it can be used at full load, but it is not recommended, or it cannot be runned for a long time, not as they describe, their generators can be used at full load for a long time. The high temperature in the cabin should be an obvious problem, they should have known the existence of this problem, but I'm thinking that the reason why they did not install the fan may be because of the reliability of the fan. And know that most customers will not use it at full load and will removed the doors. Thanks!

[@MVDirona]

Many engine rooms are poorly cooled and up well beyond 100F in the tropics. The best way to help generator cooling systems is to ensure they are operating in favorable ambient conditions (dry, warm, but not hot).

[@bassmandudge]

Hi Guys...love your videos. My wife and I are thinking about a live aboard in the next 5 years and its great to get a bank of things that may go wrong and how to fix them. Quick question...is there a reason you dont use the wing engine as a back up gen? Presumably if your only using 10bhp or so the wing is more than capable or is it just the way the engines are equipped that makes the main a better (only?) choice. Very surprised there isnt a back up gen on your boat ..so many Nordhavns have redundancy on everything ...I just get used to seeing double all the time!!

[@MVDirona]

That’s a good suggestion but harder than you might guess to realize. The wing stays exercised running the hydraulic system so it gets started whenever raising or lowering the anchor (hydraulic windlass) or operating in close quarters (hydraulic thrusters). Because it’s well sized for the backup power generation role, our first choice was to make it our backup generator as you suggest. But, 9kw of power is about 15 hp and you can’t drive 15 hp through a single V-belt. It’s hard adding an different pulley on the front of the engine since it drives the hydraulic power take off (PTO) through the front and spacing and alignment are critical there. There isn’t space to add a serpentine belt pulley and it would require a lot of custom engineering to bring it together. That makes driving the alternator load off the front of the engine difficult. On the back of the engine is a ZF-15 transmission for the emergency propulsion systems. There are no other direct PTOs on engine or transmission so there really isn’t anywhere to drive 15hp without a more engineering that I feel like stepping up to. A final possibility is to drive the alternator using the hydraulic system since it has the needed power and already has a 45cc Rexroth Hydrualic pump which is more than needed to drive 9kw load. In fact, we could go with an even bigger electrical load with this design. Nordhavn did use hydraulic generators for a few years and they worked out poorly overheating and even rarely igniting. The problem appears to have been poor control system design. There is no reason why a hydraulic generator couldn’t be made to work perfectly well. The failure mode is engaging the generator at low power output levels where there isn’t sufficient cooling of the alternator. This again is easy to avoid and a system could be designed to do this well with control system work. In fact, this was done on Nordhavn 6206 Grey Matter by Gateway Hydraulics (www.gh.com.au/) in Brisbane and it works really well. Gateway is impressively good and did a really good job of this control system and the system has run reliably for years so it’s certainly an option. We gave the wing driven hydraulic alternator careful consideration but ended up concluding it was much more custom work that we wanted to take on and required space somewhere on the boat for a hydraulically driven generator. The option of replacing the second alternator on the main engine with a large 190A@24V only took an hour, it works very well, and it works underway to drive high draw loads without having to start the second generator. We’re pretty happy with the solution.

[@bassmandudge]

@@MVDirona Thanks for taking the time for that answer ...fantastic information and really intersting stuff, especailly around Gateway and the 62.. The main engine option is certainly a simple, effective and the way to go... I had forgotten the wing gets used for the hydraulic side as well as a back up engine. I hope you fixed it ok abd looking forward to the repair video.

[@MVDirona]

The wing would be a perfect choice if it wasn't so difficult to draw more power off of it. You asked why not have a second generator? Bigger boats just about always do but in 47/52' range two generators isn't that common. I know of only one boat so equipped 4732 Bluewater owned by Milt Baker. The repair is complete and the video work is underway.

[@offgridmangogrower]

Like to know your hours on the gen when the leak began?

[@MVDirona]

We replaced the cylinder head after 6,741 hours.

[@100pyatt]

poorly spraying diesel injectors produces high EGT and cause potential heat related engine damage. A new or reman cylinder head should ALWAYS get fresh fuel injectors..... I doubt the water cooling system is the issue.

[@MVDirona]

Yes, a prophylactic change of injectors on a top end overhaul is good advice. There was no evidence of poor injector spray pattern nor high exhaust gas temperature but, since the hours were up over 5,000 and I had spare injectors, I did change them.

[@gfroese4799]

Well if you have an exhaust valve tightening [ should be called valve losing clearance ] then you really have not many choices , especially as it is accelerating which means the amount of wear is increasing at a higher rate . I have to ask though , did you also check to make sure the fuel pump was putting out the proper amount . Some engines are very sensitive to the amount of stroke on the fuel pump .

[@MVDirona]

The valve lash has suddenly become a big problem and, as you said, it's also accelerating. The engine usually goes 1,000 hours between valve lash adjustments but then one evening it closes up after only 640 hours. I re-adjusted it and it closed back up in 39 hours. I again re-adjusted it and the problem repeated in 27 hours so it's accelerating badly. This tells us that we certainly have a valve or valve seat problem but doesn't rule out injector, injection pump, or low pressure fuel pump problems. But, it's usually (but not always) the case that there is a single failure at a given time so we'll start with putting a new cylinder head on it. Since there are 6,700 hours on the injectors, I'll change those at the same time. I don't have a good way to test the injection pump so it could have problems as well. But we do know we have valve or valve seat problems so we'll start with addressing that problem and test engine operation. We feel the injection pump is likely good because the engine doesn't smoke, has good power (when valves lash is correct), and starts well but we won't be certain until we see it running after the top end overhaul.

[@frankcherry3810]

I guess you cant do a compression check like in a car engine?

[@MVDirona]

A compression test can be done on diesel engines but I've never done it and some report that they aren't as accurate on these high compression engines. In this case, it's unnecessary to do a compression test in that we know we have a valve with very rapidly decreasing lash. We know for sure there is some problem that requires the head to come off and it's very probable that it's a failing valve seat so it's best just to open it up and have a look.

[@rosskeose]

Hi, been watching your videos after your arrival in Stornoway. How long are you here for?

[@MVDirona]

We arrived to just provision and fuel since we had been at anchor in Scotland for two months prior to coming here to reprovision and fuel. Between being in Portland prior to the lockdown and arriving here we hadn't touched land for 79 days! We also had a valve seat problem on our generator as described int the video. The parts for the generator arrived last Friday night and we replaced the cylinder head over the weekend. It's back to running great. We also have a request in to the Port of Stornoway for the boat to be lifted so we can have an insurance survey done and the boat bottom painted. If we can schedule that work over the next week or so, we'll do that work before we leave.

[@rosskeose]

Thats interesting to hear. I own the workboat in the corner of the fishing harbour the Amanda J and have been admiring the Dirona. If there's anything you need during your stay in Stornoway don't hesitate to ask and I would do my very best to help.

[@MVDirona]

We have seen the Amanda J in across the harbour from us. Hello from Dirona. If we weren't all in lockdown, we would invite you over to have a look around and enjoy a beer. Over the weekend, we change the cylinder head on our generator. The valve seats were in rough shape as we guessed. It's now back to fully operational. We're trying to get scheduled for the slipway here to get bottom paint and an insurance survey but the port sounds quite busy right now. Thanks for saying hi and offering us guidance or help while we are here.

[@terrytytula]

It's a sign, install more batteries and go solar.

[@MVDirona]

There is a 1020Ahr battery bank on the house power system so we're pretty well equipped from a battery capacity perspective. And, with surface area we have available for solar, it's not possible to run on solar but it would still be a good way to reduce the generator run times. Thanks.