Yanmar 4BY2-150 Low Oil Pressure

S

South lake

Well-known member
Joined
Dec 8, 2011
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222
Fluid Motion Model
C-24 C
The other day we were out on the lake and after running for about 30 minutes at around 10 knots, I slowed our R-25 to idle and got ready to shut it off and just drift in the middle of the lake. But before I shut it off the low oil pressure alarm sounded, and the Garmin display lit up with the alarm. I glanced at the oil pressure and it looked like 12-14 psi which should be good for idle. I shut off the engine, checked the oil and found it was right on mark.

I started the engine, revved it up to 3,000 rpm's for a moment, brought it back to idle, let it idle for a few minutes and shut it off. No alarm during that process.

We spent some time just drifting on the lake and when time to leave, I started up and we cruised around with the autopilot for an hour until we returned home. Brought the boat in through our channel at an idle speed which takes about 10 minutes, tied up and shut it off with no recurrence of the alarm.

Mike of Just Dreamin' suggested that I check for a stored code in the Yanmar controller. I've looked through the book. I went to the control display, entered the menu for alarms and diagnostics but only get three choices: alarms, network status and network nodes. There was no choice for diagnostic codes although the manual showed that choice in its' display graphic.

I'm about to write this off is just one of those periodic flukes but thought I'd check to see if anyone has some thoughts on this.

Thanks...
 
When my boat was about 9 months old I was getting a low oil pressure alarm at idle. However unlike yours my pressure was showing as low. Long story short it turned out to be a bad connection from the oil sending unit at the ECU. As far as the codes go I believe you need a unit that plugs into the port hanging from the harness near the ECU.
 
Thanks... That gives me something to look for if it happens again. We had the boat out tonight and after dark ran back home at idle speed for quite awhile. No repeat of the alarm. Oil pressure was at spec all the time. We don't have any trips planned until late October so we'll keep an eye on it for the next several weeks here to see if we have a reoccurrance.
 
Well, my oil pressure alarm issue remains. it's happened several times since I launched the boat. It's almost becoming consistent. The good news is that I think, and apparently Yanmar and Ranger Tugs agree, that the oil pressure is really OK. The bad news is that so far, there's no answer as to why the alarm sounds.

I've contacted Yanmar. They don't offer much help but insinuate that Ranger Tugs didn't do something right in installing the engine or that there is a corrosion issue at the connections. Of course if Ranger Tugs bungled the installation, it didn't show up for two years. And there is zero corrosion anywhere. The boat is stored in the winter in heated storage. Aside from the first 10 hours when it was at Wefing's it has always been in fresh water. And when it's in the water it has a full enclosure over the cockpit and no water gets into any of the hatches, including the engine and battery compartments.

I've contacted Andrew and he shared that there are at least 6 other boats with the same issue. I arranged to have a Yanmar Certified Master technician come check it out and check the things that the distributor Mack Boring suggested and no luck.

I even managed to get video Sunday of the alarm sounding as I was trying to back the boat into a slip with a cross wind. Talk about composure, you can't even hear the words I muttered under my breath. Here's the video http://youtu.be/s5auBjv6qeA

My guess is that this has something to do with the ECU, the sensor, or the connecting cable. And that's all covered under a 5 year warranty. I sent Yanmar an email Sunday detailing the issue, what they and their representatives have done, and closing with the following:

I bought a new boat with a new Yanmar engine and a warranty on the electronics controlling that engine that should insure satisfactory operation for at least 5 years. I now expect Yanmar to address this problem. My admittedly uneducated belief is that the problem is in the ECU. And unless Yanmar can come up with some more realistic diagnosis I would expect you to replace the ECU, the sensor, and the connecting cable since they are the only things common to this problem in all of the boats I've been made aware of.
The boat is in the water on a fresh water lake and I will make it available for Yanmar to operate and test to diagnose and correct the problem.
Michael, when can I expect a response from you and Yanmar?

So far, no response. I'll post more as I hear from them.
 
Somebody should call Louis Garcia at :Marathon Diesel Repair, 1350 Ocean View Ave, Marathon, FL 33050,
305-743-7116
As I stated earlier I had the alarm issue a couple of years ago and Louis persisted with calls to Yanmar in Japan etc. And it turned out to be a bad connection at the wire harness. I think he even took pictures and sent them to someone at Yanmar. Perhaps if he remembers the situation he can direct you to exactly where the problem may be. To jog his memory tell him it was the Ranger Tug that was across the road staying at Harbor Cay. It occurred around 02/16/12. Maybe a few days later. I do not have my maintenance log with me, but I see a reference in my personal log as to when conversations started taking place.

Also Doug Dykens who is with Mastry Engine may be of some help. Mastry Engine is the southeast Yanmar distributor, same as Mack Boring. I believe that they may have even been taken over by Yanmar. The number I have for Doug is 727-522-9471 EXT 208.
Hopefully this may help.

Please let us know how things work out.

Mike Rizzo
 
Thanks Mike. I'll make the calls. That will at least give me something to point Yanmar to.
 
Just spoke with Louis Garcia and sent him an email with specifics. He's reviewing with the Tech that worked on your boat and will get back to me after they talk. VERY helpful guy! Thanks for the direction on this.
 
Yeah, he is very knowledgeable and an upright guy. Hopefully they have either good memories or good records!
 
Luis sent photos from when your boat was fixed Mike. They took the ground from the BY Engine Interface directly to the block. It seems your problem occurred whenever you used your forward bow thruster which is a little different than mine. but Luis is convinced that it's a grounding issue. So, I forwarded his email to Burt's Diesel and will let them make the same fix to my boat. I also expect to hear something from Yanmar as well so hopefully I'll get this solved.

Whether this solves my problem or not, Luis Garcia is a class act. He knows I'm far away and not likely to be a customer anytime soon and yet he spent time helping me without reservation.
 
Actually if you can e-mail me those pictures that would be great. mrizzo8743@aol.com. Also, if my memory serves me correctly, the alarm would go off at idle and then when using the bow thruster, but maybe it was interrelated.
 
I really like the idea of posting a video. It's very helpful, and to have the presence of mind to multitask while docking is impressive.

I had (fingers crossed) the same mysterious oil pressure fluctuation issues. I replaced the oil sending unit and things went away for a couple of months. But they came back with some other problems which I won't bore you with. They have gone away again, and here is what the mechanic said

"We think we found the problem with the oil pressure gauge. Yanmar requires the engine to have its own designated battery. The boat has its engine negative cable attached to a bus bar in the port locker. Then all other negative cables are attached to this bus bar. The engine battery negative post also has the stern thruster negative cable attached. We isolated the engine cables only to the battery and the problem went away. Added the grounds back one at a time until the problem reoccurred. The only cable suspect was the stern thruster cable. Because it was on the terminal first (with some light corrosion) then the engine cable lug on top, I think it was causing a problem. The engine cable lug should have good contact with the “lead base” of the terminal. I would prefer to see the engine battery terminals for engine only. No other cables."

This is an easy test by just reordering the ground cables on the engine battery. To be clear, I am skeptical that this has solved the problem given that it comes and goes, but it might be worth a try.

Jeff
 
Thanks Jeff. That could help. Right now I'm waiting on Yanmar to contact me and I will share this and the information I got from Mike Rizzo's recommendation through Luis Garcia. I'll keep everybody up to date as this progresses.

Andrew Custis, are you monitoring this thread?
 
Update... Two people from Yanmar are scheduled to come to my boat next Monday and Tuesday. They are assuring me that they will get to the bottom of the issue and solve the problem. They're still pretty sure it is related to the way things are grounded in the boat.

I have to say that if they follow through on this as they say they will, my confidence in Yanmar will be very positive. I'll post the results here.
 
You can thank Andrew for this new attention from Yanmar. He has put less-than-subtle pressure on them to step up and solve this problem. It pays to have an angry badger for a service rep when the manufacturer drops the ball.

The two fellows from Yanmar were supposed to be here Monday to tackle this problem, plus deal with a check engine fault alarm, since the local mechanic had been unable to resolve things. However, last Friday the alarms stopped while the mechanic was improving the ground from the engine to the battery. I tested the boat for a couple of hours on Sunday on a gorgeous San Francisco opening day and got none of the historic issues. Given that things were running fine, the Yanmar reps decided to postpone their visit, encouraging me to run the boat as much as possible to see if the problems come up again (hmmm....let me see...OK, I can do that).

The working hypothesis is that you will need a clean ground from the engine to the engine battery, including removing the thruster ground from the engine battery and putting it on the thruster battery (you can do that in 10 minutes) and disconnecting the engine battery ground from the current daisy chain of ground cables. The ECU is presumed to be hypersensitive to ground variations. No one can explain why this is the case, why it is apparently unique to Yanmar, why it is only occurring now (presumably due to minor corrosion), why it only occurs in a handful of boats, etc.

Let us know how this goes. I am going to build a cable that attaches to the engine ground and goes direct to the engine battery (about 5' long) as insurance, keeping the cable that goes to the grounding buss. Then I am going to cross my fingers and hope to be able to trust this engine again.

Jeff
 
I started this thread last September and made my last post to it in April. At that time I mentioned that Yanmar was sending a couple of people to check my boat. They spent a day and a half with me and while here made a fix much like what Jeff mentioned above and similar to what Louis Garcia had suggested (see earlier post in this thread).

I've put lots of hours on my boat since then. In fact when the Yanmar techs visited I had 177 hours on the boat and I now have just turned 265. That's almost 100 hours and the Yanmar has performed flawlessly. I'm very happy. First with the assistance from Andrew Custis and Ranger Tugs, and then from Yanmar's Michael Angland and Toby Newcomb.

I haven't posted an update until now because Yanmar asked me to wait until they released a service bulletin. Michael sent me the following message this morning:

I know it has been a long road in gathering information and data regarding the oil pressure fluctuation and low pressure alarm. We at Yanmar have done our best to leave no stone unturned. We have implemented the same procedures on several other vessels that was done on yours with the same results. I am pleased to inform you that I have released the advisory today concerning these issues. I hope you continue to enjoy your Ranger Tug. Thank you for your help with this and thank you for being a valued Yanmar customer.

My thanks to Yanmar and Ranger Tugs.
 
Good to hear that it has worked out for you. I assume now we have to just make sure that the ground wire remains clean. It should probably be an item on the regular maintenance list.
 
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