Value-oriented Replacement of Yanmar Oil Pressure Sender

[vertigo]

Regardless of which engine manufacturer you're dealing with everything but the engine core is likely from a third party supplier. I'm all for companies making profits but it's a bit much when they are tagging on 3x, 5x, 10x markups versus other sources for the same parts. The most extreme case I've personally run across was a small fan motor for a Wallas stove. Wallas wanted $60 for it and I found the same part on-line for just over a dollar. Yes, one USD. Shipping cost more than the part.

The details of your experience with that small fan motor would make an excellent post for another installment of The Cheapskate's Guide to Sourcing Aftermarket Parts for Ranger Tugs! I'd be interested to learn not just the alternate source and part number, but also the process of how you found and determined the suitability of that part. :geek:

 

[NorthernFocus]

...I'd be interested to learn not just the alternate source and part number, but also the process of how you found and determined the suitability of that part. :geek:

That was several years ago and we've long since parted ways with Wallas. So I don't have the info on supplier and part no. As to how I got there, the combustion fan failed on the stove. I took it apart and found a part no. on the motor. Google did the rest.

I worked on the Wallas stove so many times that I probably could have qualified as a service tech. Repaired/replaced virtually everything in it. Which is why I now have a Webasto furnace and a propane cook top. I like being able to fix stuff on my own. But prefer not to have to do so every time I use a piece of equipment :x

 

[vertigo]

...I'd be interested to learn not just the alternate source and part number, but also the process of how you found and determined the suitability of that part. :geek:

That was several years ago and we've long since parted ways with Wallas. So I don't have the info on supplier and part no. As to how I got there, the combustion fan failed on the stove. I took it apart and found a part no. on the motor. Google did the rest.

I worked on the Wallas stove so many times that I probably could have qualified as a service tech. Repaired/replaced virtually everything in it. Which is why I now have a Webasto furnace and a propane cook top. I like being able to fix stuff on my own. But prefer not to have to do so every time I use a piece of equipment :x

Thumbs up on finding part numbers! (...and also on the switch to the Webasto furnace.)

 

[macmac]

Unfortunately on those older stoves, there was a supplier of the same motor number you describe, but with a shorter spindle that simply could not work with the Wallas product. The longer spindle version was a Wallas custom design, only built in small quantities for Wallas, hence a high price by comparison.

Changing a motor (even the right one) requires the use of an exhaust gas analyzer and tuning the system properly, so if you want to make your own repairs, limit them to static component replacements (glow, t-couple, mat). Call for advice 1-888-606-6665.

Doug at Scan

 

[SkookumR29]

This is a shout-out and thank you to Vertigo for the research and great solution to the oil pressure sending unit issue that some owners have experienced. During our sea trial of a 2011 R29 Classic back in October of last year, the only troubling thing that came up was that when we increased RPM to something above 3,000, the oil pressure appeared to drop way off and the alarm sounded. When we dropped RPM, oil pressure went back to a normal state. Until I saw this thread and Vertigo's solution, I was not sure how to address this.

Back in February I purchased the suggested sender and thread adapter through Amazon (actually two of each since they were relatively so inexpensive) and fitted the new sender to the engine - very simple task. We did not get the boat in the water until about two weeks ago, but now with eight or 10 hours at all RPM's, we've had no sender issues - awesome.

Big thanks to all that had input on this topic!

 

[vertigo]

This is a shout-out and thank you to Vertigo for the research and great solution to the oil pressure sending unit issue that some owners have experienced. During our sea trial of a 2011 R29 Classic back in October of last year, the only troubling thing that came up was that when we increased RPM to something above 3,000, the oil pressure appeared to drop way off and the alarm sounded. When we dropped RPM, oil pressure went back to a normal state. Until I saw this thread and Vertigo's solution, I was not sure how to address this.

Back in February I purchased the suggested sender and thread adapter through Amazon (actually two of each since they were relatively so inexpensive) and fitted the new sender to the engine - very simple task. We did not get the boat in the water until about two weeks ago, but now with eight or 10 hours at all RPM's, we've had no sender issues - awesome.

Big thanks to all that had input on this topic!

I'm delighted to hear that info is proving useful to others here!

Happy tuggin!

 

[rpmerrill]

I'm mostly writing this because I want to hear more comments and also to preserve this stream of good posts.

When I first bought my R-27 it had almost 1000 hours on it. When I first noticed the pressure problem I was, at that same time, having trouble with the fuel tank sensor on my little antique car. Same kind of crazy readings. Same type of failure in the sensor.

SYMPTOMS AND CAUSES
On start up I could get a pressure reading at idle. Between ~25 and 50 psi. If the engine was still cool, and I throttled up the pressure would climb a little and then jump to something like 200 psi. (I forget, but it was scary high.). then when I would slowly throttle down it would suddenly start reading lower (in spec) pressures.

The sensor has a swing arm activated by pressure bellows. The arm swings along a small rheostat kind of mechanism, making contact with a wound wire coil. As the pressure increased the swing arm moves up and the resistance increased. A higher resistance is read by the computer as a higher pressure. A break in the wire coil gives an infinite resistance as soon as the slider crosses over to the other side of the break. The break in the coil wire is usually caused by wear/vibration. If you cut the sensor can open you could actually see the wear point(s). Of course on an oil sensor it spends most of it's time up at about 60 psi where we cruise most often. So if you're getting these kinds of symptoms the sensor needs to be replaced. (Moving the sensor off the engine might be a very good idea.)

That's the only known type of sensor failureI know about.

There was one more item I wasn't able to learn the answer to. Good grammer?
Low oil pressure alarm. Where is a low pressure alarm generated?
In diagnosing my sensor issues, I ran my engine with no sensor, just a pressure gauge. I had disconnected the wires and shorted the wires.... Nothin'.

Yet when I started the engine, I'd get an oil pressure alarm for 5 seconds or so every time.
Back when I first posted this question nobody seemed to know how the alarm is generated.
Anyone?

 

[ALICE J]

Ranger 27 2011, 4BY 180, 2200 hrs . Recently noticed when I start the engine, oil pressure reads about mid 50’s for about 10 minutes the drops to mid to low 20’s, At about 1800- 2000 oil pressure stays mid 20’s , at higher rpm pressure is mid 50’s, haven’t noticed if it drops to the 20’s, will pay attention next time. The comment about wear, vibration, and heat make sense.

 

[vertigo]

There was one more item I wasn't able to learn the answer to. Good grammer?
Low oil pressure alarm. Where is a low pressure alarm generated?
In diagnosing my sensor issues, I ran my engine with no sensor, just a pressure gauge. I had disconnected the wires and shorted the wires.... Nothin'.

Yet when I started the engine, I'd get an oil pressure alarm for 5 seconds or so every time.
Back when I first posted this question nobody seemed to know how the alarm is generated.
Anyone?

That's an easy one to explain. Your BY-series Yanmar engine is equipped with two sensors. The one at the top front starboard side sends a resistance reading that is translated at the panel to a pressure indication. There is another sensor under the oil filter on the port side that acts as a switch informing the engine computer whether there is at least minimum oil pressure. That is the sensor that kicks off that alarm, and the minimum oil pressure is determined by the function of that sensor -- typically at around 7-11psi for the stock sensor if I recall correctly.

 

[rpmerrill]

Aha!
I'll have to take a look for it. About 4 years ago nobody knew.
It's reassuring that there really is a sensor actively monitoring the pressure. Apparently it is more reliable.
Wonder what it costs?
Thanks much.

 

[vertigo]

Aha!
I'll have to take a look for it. About 4 years ago nobody knew.
It's reassuring that there really is a sensor actively monitoring the pressure. Apparently it is more reliable.
Wonder what it costs?
Thanks much.

You can buy a VDO OEM direct replacement for it for less than $40. Even less for no-name copies.

 

[Boatdreamer]

Good Morning, I have a question about the oil pressure sending unit. Several months ago I noticed my oil pressure swinging wildly on my way to the Southwest Florida rendezvous so I put that on my to-do list. I found this thread (a big thanks to Vertigo) about a cheaper solution so I ordered it along with the adapter. I cleaned the terminals on the old one to see if that was it. We took Gratitude out for a ride yesterday and the oil pressure was normal throughout the RPM range so I thought I was home free. Well we were almost back to the boat ramp and the super dependable Yanmar shutdown. I did some quick trouble shooting and found out the oil pressure had dropped to 19 PSI and shut down the engine. I’m changing the the sensor today but is that how it’s designed to protect the engine or do I have another issue? When we got back to the dock she started right up and ran fine. I thought the engine would go into limp mode but it didn’t.

Tim and Donna
Gratitude

 

[vertigo]

Good Morning, I have a question about the oil pressure sending unit. Several months ago I noticed my oil pressure swinging wildly on my way to the Southwest Florida rendezvous so I put that on my to-do list. I found this thread (a big thanks to Vertigo) about a cheaper solution so I ordered it along with the adapter. I cleaned the terminals on the old one to see if that was it. We took Gratitude out for a ride yesterday and the oil pressure was normal throughout the RPM range so I thought I was home free. Well we were almost back to the boat ramp and the super dependable Yanmar shutdown. I did some quick trouble shooting and found out the oil pressure had dropped to 19 PSI and shut down the engine. I’m changing the the sensor today but is that how it’s designed to protect the engine or do I have another issue? When we got back to the dock she started right up and ran fine. I thought the engine would go into limp mode but it didn’t.

Tim and Donna
Gratitude

That's a very good question whether the Yanmar engine control unit actually has a fail-safe shutdown protocol for low oil. I'm not aware that it does, and rather suspect it does not from my own diagnostic experimentation. I've disconnected both the pressure sensor and sender leads with the engine running at idle without any result other than the expected alarms, though I don't recall whether that was alternately or at the same time.

Perhaps there is a routine for shutdown after extended low oil reading, but I'm doubtful that it would trigger at 19psi. It is theoretically possible that your sensor was reading false high at 19psi, but the sender below the oil filter would trigger an alarm at about 07psi, and it seems even less likely that both would go inop at the same time. Were you hearing an oil pressure alarm before shutdown?

I'll bet there's expertise to the rescue soon here on this thread.

 

[CaspersCruiser]

That's an easy one to explain. Your BY-series Yanmar engine is equipped with two sensors....

Learning has been achieved. If I knew this BY information, I had forgotten it.

 

[vertigo]

If I knew this ______ information, I had forgotten it.

I find myself saying that more and more lately. 🙂

 

[Boatdreamer]

Good morning Vertigo, I’m really trying to remember the chain of events but I think the engine alarm went off and I looked down at the Garmin and it said something like check engine oil then it shut down. I was out in the middle of the river so we didn’t have any concerns about hitting anything or being hit so I took my time checking everything I could think of. I tried to restart the engine but when I turned the key nothing happened. I happen to look at the Garmin the next time I tried to start it and the message was like engine neutral safety switch. I had forgotten to bring the gear shifter back to neutral and on top of that the autopilot was still engaged. I tried to start it and it fired right up but we got about a 100 feet before it shut down again. Oil looked good, water temp looked good so it was time to call Towboat US and have lunch. I’m replacing the sending unit this morning with the setup you recommend and then a test run tomorrow or Wednesday depending on the weather. Bill, I’m going to order the other sensor by the oil filter just in case I need it because I have just a little bit of space left in my spares box and I love my spare parts! I’ll keep you posted.

Tim
Gratitude

 

[knotflying]

You could possibly have two things going on at once. In the past when there was the oil pressure loss the engines did not shut down. When it was one of those past hose ruptures some people blew the engine because it did not shut down. First question is, did you take care of the service bulletin related to erroneous oil pressure readings? This requires rewiring the sending unit differently and a software update on the control unit. Secondly, did you check the error codes via the Yanmar display? Before I did any changing of things I would see if I could pinpoint the problem. Once you start changing things diagnosis gets harder.

 

[vertigo]

You could possibly have two things going on at once. In the past when there was the oil pressure loss the engines did not shut down. When it was one of those past hose ruptures some people blew the engine because it did not shut down. First question is, did you take care of the service bulletin related to erroneous oil pressure readings? This requires rewiring the sending unit differently and a software update on the control unit. Secondly, did you check the error codes via the Yanmar display? Before I did any changing of things I would see if I could pinpoint the problem. Once you start changing things diagnosis gets harder.

I tend to agree with that advice, especially about pinpointing the problem, but sometimes changing out sensors it the best way to determine whether the sensor was to problem. Firstly, though, I'd make certain that the engine is making oil pressure when started, and that's why I added the good old-fashioned steam gauge to my remote sensor mod in the engine compartment so that I can visually confirm direct pressure readings rather than rely solely on instrument interpolations of electrical resistance.

Tim, I would start by removing the suspect sensor and installing a physical test gauge to confirm actual oil pressure readings. If the engine really isn't making oil pressure, you'll want to know that right up front before it can do real damage.

 

[Boatdreamer]

Hi Mike, no I didn’t do the service bulletin for two reasons, if it isn’t broken don’t fix it and I forgot that it had a time limit on it and now it’s too late. My plan moving forward is as Vertigo suggested using a gauge to verify I really do have oil pressure first then change out the sensor if I do. I ordered a simple cheap gauge yesterday from amazon so I’ll be doing that on Thursday. Today I’m changing out the primary fuel filter and I’ll be checking for water. I’m also ordering the small sensor under the oil filter housing just so I have it available. Thanks everyone for the helpful suggestions, I’ll report back what I find.

Tim
Gratitude

 

[vertigo]

Hi Mike, no I didn’t do the service bulletin for two reasons, if it isn’t broken don’t fix it and I forgot that it had a time limit on it and now it’s too late. My plan moving forward is as Vertigo suggested using a gauge to verify I really do have oil pressure first then change out the sensor if I do. I ordered a simple cheap gauge yesterday from amazon so I’ll be doing that on Thursday. Today I’m changing out the primary fuel filter and I’ll be checking for water. I’m also ordering the small sensor under the oil filter housing just so I have it available. Thanks everyone for the helpful suggestions, I’ll report back what I find.

Tim
Gratitude

I'll be especially interested to hear the results of your diagnostics.