Finally! We have a clear identificaiton of the cause and have fixed the issue. Following my earlier post in this topic, I sent along the writeup and video to the Nordhavn Owners Group, which has some 750 members including owners and top marine experts familiar with Norrdhavn systems. This group is an incredible resource representing a wealth of experience, and sure enough, I got some very good suggestions for potential causes and methods to troubleshoot the issue. I shared these with the Philbrooks staff and they started in on it Monday morning, Sept 30th.
The key was the “bucket test” suggested by Bob Senter of Northern Lights/Lugger (the engine manufacturer). The idea was to get a bucket filled with fuel and run short supply and return lines direct, bypassing the entire fuel delivery system. If everything is fine, you know that the issue is with fuel delivery. If not, you suspect the engine (fuel pump, inejector pump, etc). The philbrooks guys did a variation of this using clear hose so they could see what was going on.
Long story short, there were obvious, large, frequent air bubbles in the clear hose when connected to the boat’s fuel delivery system. No such bubbles (obviously) when straight to the bucket. Now the issue was to identify the source.
By the end of the day Monday we were able to go out on a Sea trial on which we bypassed the primary fuel filter assembly (which contains two replaceable fuel filters and allows you to select which one to draw fuel through). The engine ran perfectly, not skipping a beat. The conclusion was that there was a leak somewhere in that manifold, so a new one was ordered to arrive mid-day Tuesday. Unfortunately, testing at the dock after installing the new manifold still revealed air bubbles, to be chased down on Wednesday.
On Wednesday we identified a problem with the fuel selector valve in the new manifold that allowed air into the lines. Tightening that valve elminated the problem, but there were still air bubbles getting through. The source was determined to be the supply lines from manifold to the engine. These were replaced, and the Algae-X filter removed just for good measure. A final sea trial proved that all of the air bubbles had been eliminated, and the Maretron fuel flow sensors, now reconnected, showed a very steady rate of fuel consumption. Here is a clip showing the display at our normal cruising RPM and another at WOT.
We are going to depart directly from Philbrooks to Neah Bay today (Thursday, 10/3/19) and will be making the passage down the coast on our own, with the help of our weather router, Bob Jones of Ocean Marine Navigation Inc.
As Gwen wrote yesterday we were finally ready to head off on our journey down the Pacfic Coast, trying to catch an elusive and narrow late season weather window. We were a bit nervous prior to departure as the forecast were for gales and small craft warnings down the Strait of Juan de Fuca. The worst of it was to be right at the Eastern end, so we made a pre dawn departure to, hopefully, avoid the worst.
When embarking on a trip like this, particularly with the possibility of encountering bad weather, you do not want to hear your trusty Lugger diesel engine begin to slow down spontaneously. We thought we had resolved the RPM variation issue by replacing the fuel flow sensors, as I described last week. Apparently not. It only took a couple of cycles of this to realize we weren’t going anywhere.
OK, now you know what happened. If you don’t want to read a bunch of geeky stuff about trying to fix fuel flow issues with diesel engines, this might be a good place to stop.
Because this is an ongoing issue, I pulled out my phone to capture some video of what was happening. I compiled a short compilation of those clips in hopes that it will be helpful in trying to diagnose and finally resolve this problem. I’ll include a link at the end of this post.
What we saw and heard
While cruising at our normal 1800 RPM, a spontaneous drop of > 200 RPM, which was very obvious listening and watching the tachometer. The engine would slow down, stay at lower RPM for a moment, and then speed back up to the “right” RPM. Several instances of this are illustrated in the video. We also saw this when running at Wide Open Throttle (WOT).
As this was happening, the Maretron display showed large fluctuations in fuel flow as recorded by the inline sensors. It looked like the decrease in RPM was associated with an increase in reported fuel consumption, but it is hard to be certain because the system averages readings over a 5 second window.
There did not appear to be any fuel restrictions as would be measured by the fuel supply vacuum gauge, which is mounted on the fuel filter manifold. In fact, the reading we saw on the gauge was 0, surprisingly low, and meaning no fuel restriction.
Troubleshooting and attempted fixes
Diesel engines are pretty simple and very reliable. According to Wikipedia:
Diesel mechanics say that 90% percent of issues are due to fuel delivery, so we decided to work our way through the fuel system from supply to return in order to identify and eliminate potential causes. Here’s what we did:
Inspected and replaced the Racor primary fuel filters. These are the first stage of filtration, making sure that the fuel to the engine is clean. If there is contamination in the fuel, these filters remove it. They eventually need to be replaced. The indicator is the vacuum gauge I mentioned earlier. There was no symptom of high vacuum, but the filter had not been replaced since we started our trip to Alaska, so we replaced it. By the way, the system actually has two filters, so if one gets clogged you can easily switch the the backup.
Replaced the Lugger secondary fuel filter. This one is mounted on the engine and is the final stage of filtration. It was replaced this summer while we were in Alaska but had not been replaced since the tanks were inspected and the sensors installed, so we did this one as well.
Inspected and cleaned the Algae-X filter, which is some odd contraption that a previous owner had added. It is essentially a housing with a magnet in it, through which the fuel passes on the way to the engine. I suppose it is yet another stage of filtration, but it is entirely unclear that it actually does anything. Nevertheless, we disassembled and inspected it. All clean.
Having done all of this, and “bleeding” the fuel system to make sure no air remained in the system after changing filters, we started up the engine. We ran it up to 1800 RPM at the dock, and still saw the RPM (and fuel flow display) variation, even when the engine was running in neutral under no load. So, clearly none of these items were the cause of the problem.
Next, on the advice of the knowledgeable mechanic that replaced our fuel flow sensors, we “bled” the high pressure side of the engine, which involves loosening the fuel injectors while the engine is running to ensure that no air is trapped in the system. This had no effect – same symptoms when running at 1800 RPM at the dock.
Finally, we bypassed the Maretron fuel flow sensors using a couple of fittings to connect the fuel supply and return lines, respectively.
At this point we were out of ideas, so time for a sea trial. Unfortunately, the variation was still present… smaller and far less frequent, but noticeable both by the sound of the engine slowing down and watching the tachometer needle drop and rise back up. This time it seemed to be less noticeable at cruise RPM, but clearly evident at WOT (as shown at the end of the video). So, I think we can conclude that the Maretron sensors are not themselves the cause of the RPM variation. Now we need to turn to the fuel system on the engine itself, perhaps the fuel injector pump or even the injectors.
Bottom line… back to the yard. We plan to limp over to Philbrooks in the next day or so, which will be our new jumping off point for the trip South.
After some late night and early morning detailed weather reviews, we cast off the lines and headed out toward the Strait of Juan De Fuca and Neah Bay.
The weather was beautiful and calm and it looked like we would beat the northerly winds by heading west out the Strait.
Well, the gods, or maybe the furies, are not smiling on us today. Or maybe they are by having us face this engine issue before we are out at sea.
Only a mile outside of the marina the engine showed very significant RPM decreases. This only had to happen a couple of times for us to make the decision to turn around and head back and figure out what the heck is going on.
So we are back in our slip. Larry and Steve spent the day going through all the easy to fix and diagnose items like fuel filter clogs, taking the fuel flow monitors out of the circuit, etc. We thought we might have fixed it and took the boat back out to trial it, but the spontaneous RPM variations continued.
We will be making a trip to the yard for diesel work rather than down the coast over the next few days.
More to come as we figure out what the situation is.
The best laid plans of mice and men often go awry. RobertBurns
I am writing this on Friday, September 20th, which was to be our departure date for heading down the Pacific Coast to California and then on to Mexico with the 2019 CUBAR Rally. Well, things have not gone quite according to plan, and it is kind of a long story, so go grab a beverage, sit back and relax (or go read something more interesting).
I am sure that many wise and experienced boat owners have said something along the lines of “Never have major boat work done just before a big trip”… I think we now know why. As I mentioned in an earlier post, we put Miss Miranda in the yard right after returning from Alaska with what somehow became a lengthy project list. The good news is that the vast majority of the work was executed flawlessly and we are very happy with the improvements. The bad news is that a couple of items were not quite right, and they are critical. I know those same wise boat owners also said “Make sure you do a sea trial with the yard before leaving to ensure that EVERYTHING was completed to your satisfaction”. Good advice. Why didn’t I think of that?
The biggest issue that we discovered was a problem with the newly installed fuel flow monitoring system. This is intended to display the engine’s fuel usage and economy while underway. On diesel engines, fuel passes through the engine and about 20% is actually burned. The system uses sensors that measure fuel flow to the engine and back from the engine and from that computes fuel usage. While on our way back to Anacortes, we noticed that the fuel burn readings were very erratic while we were running at a constant RPM, and that the engine RPM was varying slightly… but enough to be a concern, as it had never happened before. To make a long story short, the sensors installed were undersized for the engine.
We found another issue as we were fueling up for the trip. We let the fuel level on the boat get really low on the way back from Alaska so that we could have the tanks inspected. They were in great shape, and the fuel was polished and returned to the boat. We measured the remaining fuel to calculate how much we needed to take on using our “tank tender” system. All went well until we came to the starboard aft tank, which measured as empty. We started filling the tanks and almost immediately got fuel flowing back from the vents. That is obviously not what is supposed to happen. I crawled into the lazarette and discovered that the sender from that tank had been broken off. The empty reading was false, and the tank was actually full (or very close).
The yard’s response to these issues was great – they arranged to have a technician come to us in Anacortes to do the repairs. Fortunately, I was able to secure a pair of the proper fuel flow sensors locally, because they were on back order from the Maretron factory. So far, all good with our tech scheduled to arrive on Wednesday morning.
Then I made a very unpleasant discovery in the engince room. There was a line of red fluid across the floor which seemed to be coming from the wing engine. It turned out to be Automatic Transmission Fluid from the gearbox. Not good.
The mechanic arrived on Wednesday and took care of the fuel flow sensors and the tank tender, and then turned his attention to the fluid from the wing engine. The diagnosis was bad main seals (that go around the propeller shaft), and the bad news was that it was not possible to replace the seals or rebuild the transmission. We had to either buy a new transmission or put a drip tray under the transmission, keep a large supply of fluid on hand, and hope for the best. Lenny, our technician, had replaced these units before, and assured us that he could replace ours pretty quickly. It turned out that a shop down in Everett had one in stock, so off went Gwen for a little ride to pick it up. It was late in the day by the time she got back, so we planned for an early start the next morning.
Of course, nothing goes quite as planned… the old transmission did not want to come off, and in the struggle to remove it, Lenny cracked one of the mounting plates. Furthermore, I was told that Lenny needed to get back to his regular clients and would have to leave, finished or not, at the end of the day. Some discussion with the transmission shop led to a solution for removing the old transmission, but involved yet another trip to Everett for Gwen.
Lenny was finally able to remove the old transmission and got the new one painted while we waited for Gwen to return. Amazingly, he was able to install the new transmission, align the prop shaft, and test the wing (at the dock) and still make his 4 PM ferry back home. Lenny is an outstanding marine technician, and we greatly appreciate his mechanical wizardry.
As all of this was happening, we had a call with our weather router, who suggested that we delay our departure until (at least) Sunday to avoid a frontal system moving across the Washington offshore waters. We were not unhappy about this, as all of the unexpected repairs had put us behind schedule in loading up the boat.
We got out on the boat for another sea trial on Friday 9/20. It was all good news. The wing engine worked flawlessly, and the fuel monitoring was much more consistent, with no more RPM variation.
Now we are busy with the final preparations and waiting on the weather window. We have another call with our weather router today (9/21) to determine if we are still on for a Sunday departure.
We are here in Sidney, BC waiting to meet with our project manager for our final visit to Philbrooks before heading South down the Pacific Coast. We planned this visit earlier in the year, knowing that we could not get all of the work done before taking the boat down to Seattle for Opening Day in May. Therefore, we prioritized the work we thought needed to be done before Alaska and that which could be done afterwards. And, of course, we knew that unexpected items would turn up on our Alaska trip…. and man,were we right about that.
The work list contains a mix of preventive maintenance items, repair or replace items, and a number of upgrades. Here are some of the things we wanted to do specifically related to cruising in Mexico:
Solar panels. We are adding about 1000W of solar on the pilot house roof. We had originally hoped to have these in place before heading to Alaska, but they got bumped to this visit.
Flopper Stopper setup for at anchor stabilization. We have heard that many of the anchorages in Mexico are exposed to swell and thus quite rolly. The flopper stopper is a rig consisting of a pole that swings out from the port side of the boat with a line that goes down to a plate deployed into the water. The plate has slats in it that allows it to sink easily, but not rise, thus minimizing side to side rolling. Many Nordhavns have this setup.
Interior DC fans. We do have four zones of Air Conditioning on the boat (which is one of the preventive service items) but we want to minimize our use of it, because it requires either running the generator or being connected to shore power. Therefore, we are going to place 8 fans in the salon, pilot house and staterooms with the goal of maximizing air circulation.
Sun Shade for the boat deck. When we put the dinghy down, there is a large amount of usable space on the boat deck. We will rig a sun shade to maximize the use of the space.
A second autopilot system. We already have redundant GPS, Chart plotters, and radar. We think it is also important to have a back up for the autopilot.
Replace galley refrigerator and convection/microwave oven. We planned to replace the refrigerator, which is a 20 year old domestic refrigerator and a real energy hog. We did not anticipate replacing the convection/microwave until the beginning of this trip, when the touch panel of the existing unit failed. It mysteriously started working again, but just to be sure, we will replaced it while we can.
Upgrade the engine room cooling system. Engine room cooling has been an issue with many Nordhavns. With a dry stack exhaust system, there is a lot of heat that needs to be removed via air circulation, and without proper circulation, the engine room can get quite hot… sometimes hot enough to impact the reliability of some components. The typical specification is that the engine room temperature does not exceed the outside air temperature by more than 20 degrees. We don’t meet that goal even operating up here in the Pacific Northwest, with very cool seawater for the keel cooler and low ambient temperatures. So, we are going to follow the lead of other Nordhavn owners who have installed extraction fans up in the stack to pull the hot air out of the engine room. We will also replace one of the existing blowers that failed on our Alaska trip.
Haul the boat out of the water and look at our propeller and bottom paint and do any service required. We didn’t hit any ice or logs of significance so we believe the propeller is in good shape but want to be sure.
Maybe… figure out a stern anchor solution. We have heard that a stern anchor is somtimes helpful in open anchorages in order to keep the bow pointing into the prevailing swells. We have a spare main anchor (a Fortress SX-55) that we have used once as a stern anchor, but the time taken to assemble it and drag the rode from the foredeck storage box makes it very inconvenient to use as a stern anchor. It would be nice to figure out a way to have a smaller anchor that is easy to deploy from the back of the boat.
I think that does it for the “planned” work. Some of the repair or replace items that came up on our trip North include:
Patch the tube on the dinghy. We were in Prideaux Haven going to our favorite swimming hole and preparing to anchor the dinghy next to a large rock. The rock had numerous oyster shells that were exposed at low tide, and we drifted into one that made a two inch gash in the tubing.
Replace the motor on the diesel heater. We rarely use the diesel hydronic heating system in the summer, but needed it on one 40-something degreee morning in Alaska. Of course, it didn’t start. Some great support from Sure Marine Service in Seattle helped dignose the problem, which was the motor. The diagnostic tool? A rubber mallet. “Start the system, and rap the motor with a rubber mallet. If it starts up, you know you have a bad winding and the motor needs to be replaced.” Yup.
Replace the Furuno GPS. We have three separate GPS sources on the boat including this older Furuno GPS, which connects directly to a Furuno RD-30 display unit to show speed over ground, position, wind data, etc. When we were crossing Cape Caution on the way up to Alaska, the GPS stopped transmitting data… of course when the seas were up and the boat was moving around quite a bit. No big deal to switch to another source for the NAV equipment, but time to replace the old unit. I elected to replace the receiver only and still have it connect to the RD-30, and from there the NMEA bus.
Replace the generator injector pump. I mentioned this in an earlier blog post and actually got a replacement pump sent into Petersburg. However, the fuel leakage had decreased to an acceptable level, and seeing that a miscue in removing or replacing a connecting clip would have serious consequences, I wimped out and elected to have Philbrooks do this.
Add delay switches to the windshield wipers. This one sounds odd, I know. The boat has four wipers, one across each piece of the pilot house windshield. The wipers are needed for rain, obviously, but also for clearing salt spray in boisterous sea conditions. Each of the wipers has a separate 3 way switch for off, low, and high speed. In all but hard rain (which we had plenty of in Alaska), the low setting is still too high. Thus, one will be constantly switching the wipers on and off. Trivial, but annoying when running in crummy weather. We should have done this before going to Alaska, but it was only when we got up there that I realized just how much of an annoyance this was, and how easy it is to fix. Just add $$.
After a full day of meeting with the various departments at Philbrooks, everyone has a good idea of what needs to be done, enough so that we have established a tentative pick up date… September 13th. If all goes well we will take the boat back to Anacortes, load it up and start heading South on September 20th.
I am thinking that maybe I should not have made the service opportunity blog post. It seems to have prompted new service opportunities. The current one has to do with the… shall we say… sanitation system. Most of us living on land rarely give this topic a thought, but it is very important on a boat. In our home cruising grounds all Marinas have pump out stations, where we can remove waste that accumulates in our holding tank. That is not the case way up here. Therefore, boats are equipped with an overboard discharge pump, which does exactly what the name implies, of course only in locations (offshore, deep water) permitted by Coast Guard regulations (and common sense).
So, what to do if said pump does not appear to be in working order? Check all of the easy possibilities first… maybe the vent is clogged, maybe the through hull is blocked, maybe the tank tender is not reading correctly. When that is done, you recall that you had the system serviced in May, wanting to avoid just this situation… and you also recall that you do not have a replacement pump or spare parts on board. Uh Oh. Fortunately, we have both phone and data service where we are, so I was able to look up the model numbers for the relevant parts and call Piston and Rudder in Petersburg to see if they can order the pump and/or parts for me. I feel that I am getting to know them quite well, since they also ordered the generator fuel injector pump for me.
We should find out today if they can order parts, and we plan to be in Petersburg by Thursday or Friday. Then the real fun can begin…
Meanwhile we are enjoying beautiful Takatz Bay (post coming) and a couple of sunny days.