Yanmar 4BY and 6BY Information

J

j&lgray

Well-known member
Joined
Nov 28, 2008
Messages
644
Fluid Motion Model
C-28
Vessel Name
Trilogy
Greetings Owners Of These Legacy Ranger Tugs;

We have been owners of three Ranger Tugs for a combination of 12 total years, a 2007 Ranger 25 with the Yanmar 110, 2012 Ranger 29 with the Yanmar 260 and currently have a 2012 Ranger 27, Trilogy, that we are using it to do the Great Loop for the second time only in segments. I want to share with you information that was recently obtained from a variety of sources including owners at the recent SW Florida Rendezvous. I am not an engineer or mechanic, I just do as much of my own work as possible and try to learn from those who know more than I. I hope this thread will be used to predominately share great information about these engines. Bottom line: these are still great engines.
 
Issue - Engine Alarm, "Main Throttle Sensor;" This went from an occasional issue to a daily one. First the RPM's would fluctuate 2 to 4 RPM's. After two minutes of this, a visual and audible alarm came on the Garmin and Yanmar displays with a dialogue window, "OK or Configure." Selecting OK, made the visual alarm go away and the fluctuations stop. Turning off the engine, reset the error codes. When two authorized Yanmar dealers either did not have the computer to read the ECM or had no knowledge of these electronically controlled engines, I was referred to the experts at Mastry Engine Services in St. Petersburg, FL.

The fix, Mastry Engine Services in St. Petersburg had the experts to quickly determine that two connections of the engines network cables (or harness) that transmits mili-volts from sensors to the ECM were loose. One connection had water in it because it was installed right under the engine hatch gutter. Those connections are twist, threaded connections and those plastic collars should be tight. The connections can be easily disconnected by unthreading the collar and pulling them apart. The mechanic was very explicit to clean these multi-pin connections with brake parts cleaner and NOT to use dialectric grease that I commonly use on 12 volt connections. Any material on these pins increases the resistance and the ECM will detect and respond to the change of voltage. When re-assembling the connections, use the guides on the plastic barrel pieces to line-up the connection and then use the collar threads to bring the connections. Common error: line up the pines and push them together. The pins get bent or broken.

The issue went away and has not returned.

Most of the Ranger 27's with the Yanmar have the barrel connector under the engine cover gutter and is cable tied to the scupper drain hose. This should be protected from water exposure. I took a water bottle, cut and split to size and cable tied it around the connection.

Information: The Yanmar engine display has a wealth of information about the engine status and alarms. Start with the screen that looks a speedometer only for RPM's. Then hold down the button on the far right for 3 to 5 seconds and the alarm status window will display that can be toggled through.
 
The mechanic at Mastry Engine Services, a company that is owned by Yanmar and provides technical services and materials to their dealer network and provided this information:

Issue - Oil Pressure Reading. BMW first put the oil pressure sender on the side of the oil filter element canister. It was moved to the top of the engine. The hole from the old sender has a plug in that is easily accessed on the side of the oil filter canister near the bottom. CHECK that plug for being tight every time the oil is changed. That plug has come out causing total engine failure. The oil pressure sensor is on top of the engine under the starboard side engine cover in the forward corner. Some times that sensor goes bad and is easily replaced. Very dirty oil will also affect that sensor. Getting low psi readings? The first step should be to change the oil. Given a choice, always believe the engine alarm and not the reading of the psi gauge.

Issue - Sudden poor engine performance at all RPM's. There is a sensor in the air intake manifold (yes, it is plastic) on the top of the engine, port side, under the engine cover and forward. That sensor is held in with a half a turn. It has come out causing an unwanted amount of air into the system. The sensor can be easily put back in with the wiring intact.

Issue - No power above about 1,800 RPM's. This may be caused by an issue with the turbo that can be relatively easy to handle. Take off the air cleaner and look inside with a pair of needle nose pliers. The vanes on the turbo should move easily. If they do not, use the needle nose pliers to gently break them loose of the sentiment that is causing them to stick. When the vanes move fairly well, make up a solution of Dawn soap and water in a spray bottle, 1/4 soap to 3/4 water, run the engine so the turbo starts turning and spray the entire contents of the bottle into the turbo.

Info - Yanmar like to run hot. Remember the thermostat opens at 190 degrees.

Info: These engines are not necessarily orphans. It is true, these engines are not for sale by dealers and boat builders in the U.S. However, these engines may be available by special order from Europe. The wait is 3 to 4 months and they want the money upfront. I saw a 6BY-260 engine in a box that had just arrived from Europe and was waiting to be installed. These BMW engines are proven and have a long history of great service.
 
Issue - Serpentine Belt Health & Replacement. The serpentine belt is on the front of the engine and most engines had the front guard removed during installation. The belt is loosened by putting a 1/2 drive socket wrench or breaker bar into the center of the spring loaded tensioner and rotating it away from the belt. If you not see belt dust on the surfaces under the belt, the belt is probably still good. Another symptom is the alternator is not charging like it had before.

Always carry a spare serpentine belt.

Issue - Impeller and Seawater Pump. Owners have a variety of ways to address this because the installation of the engine made access to this very difficult (mechanic said this was 9.5 on a scale of 10). Some owners have cut into their front step to get more access. Others and the mechanic I saw, could reach down, remove the separate belt from the water pump pulley, remove the four bolts (using scotch tape on each one so not to drop it) and pull the impeller. The seawater pump has seals that fail. Mine did requiring a total overall. The signs of seal failure - using a camera to photograph the pump showed green lines on the seam or water in the bilge that is not cause by the drive shaft coupling. Signs of impeller weakness: water is not being propelled out of the exhaust in a forceful way or the coolant temperature is routinely 205 degrees or higher.
 
Issue - Gear shift cable does not work, broken or kinked causing hard shifting. Typically this is not repairable and a replacement is needed. Replacing is done by using the old cable as the means to pull the new one through the tight spaces behind the interior walls. For the Ranger 27, these are Ultraflex cables and are 21 feet long. Consider replacing it with a 22 foot long cable that allows a wider arc and causes less strain on the cable at the engine.

Issue - Engine Anodes Replacement. If these have not been replaced, the bolt heads or the anode are the same color as the engine and use the operating manual to locate them. On the 4BY there is a plug that is between the two anodes. If you take it out by mistake, put it back it. The top anode is threaded into cavity in the block that is only bigger than the anode with a 1/16 to 1/8 hole at the end. Use a set of picks to scrape out the cavity and leftovers of the anode and clear out the small hole so seawater can get through.

Issue - Adding Coolant. Check BOTH the coolant reservoir and remove the cap on the top of the engine. When this cap is difficult to remove, take a large channel lock wrench and use the tips pointed straight down against the sides fo the cap's two shoulders to free it. Several owners have found the coolant reservoir was at the proper level but the engine itself took considerable amount of coolant. The symptom: engine was running hotter than normal.
 
Issue - Power, Performance and Prop Size/Pitch. Is there an issue with your boat? Find out by fully loading with people, equipment, fuel and water and on a calm flat day, and after the thermostat is open at 190 degrees, bring the engine up to its maximum RPM. If your Yanmar engine is between 3900 and 4100 RPM, you are fine. If it is off by even 200 RPM and there are no other mechanical (the engine display will measure % of load and turbo PSI and these and indicators of engine issues) or bottom issues (like lots of growth), then consider talking the propeller to a propeller shop to get the right prop on your boat. All they need is your RPM data from the test and your prop to make the adjustments.

Why is this a big deal? If the prop is not correctly matched to the boat's condition, the engine will be under enormous stress at all RPM's which may lead to a shorten life span, pre-mature failure and repairs. This is an issue that mechanics have reported involving theses higher RPM engines.
 
Replacement Filters and Other Parts: I am keeping a list gleaned from sources including this forum about where to find filters and parts for these engines and boats. If you want to contribute to this research, please send me the make, model and other information about the filter, belt, or part to me.

A private message or PM may be better than using this thread. Then, I will post all of it here. One place for all of us to see and share, but a lot of knowledge that keeps these boats fun and working.
 
Yanmar owning Tugnuts: Bookmark this thread. I got personal instruction on many of these items from John at my R27 during the 2020 SW Florida Rendezvous. Great information.
 
j&lgray":2hcdibat said:
Replacement Filters and Other Parts: I am keeping a list gleaned from sources including this forum about where to find filters and parts for these engines and boats. If you want to contribute to this research, please send me the make, model and other information about the filter, belt, or part to me.

A private message or PM may be better than using this thread. Then, I will post all of it here. One place for all of us to see and share, but a lot of knowledge that keeps these boats fun and working.
Click to expand...

Here's a link to my post in another thread with aftermarket replacement parts for the seawater pump (a Johnson Pump OEM for Yanmar) used on the 4BY and 6BY engines:
viewtopic.php?f=5&t=14659#p97110

Here's an inexpensive source for impeller replacement parts for the Yanmar BY series engines:
https://www.amazon.com/gp/product/B01BE ... UTF8&psc=1

And here's a thread on replacing the vastly-overpriced $275 oil pressure sender on these engines with the exact same unit minus the Yanmar cardboard box for $55, or adding a thread adapter and using an equivalent US-thread unit at $36:
viewtopic.php?f=5&t=14629
 
Thank you John for all the hard work that went into your post. It’s great to see the Ranger Tug/Yanmar community has so much wisdom for us owners to pull from. You talked about several items I need to address with our 4BY2-180 in the near future to keep it running for many more years. I really enjoyed talking to you at the rendezvous and I look forward to seeing you at the next one so we can finish our conversation.

Tim and Donna
Gratitude
 
For the newer owners of these "Classic R27's, we have the experience and knowledge of specifically Mike on Illusions and Tim on Gratitude to learn from. Besides this forum, they are responsive to PM (private messages) if you need help.
 
Replacement Filters, Part 1.

Please understand this disclaimer, we have tried to provide the best and accurate information but it is up to you the owner, to verify that it is the right part for your engine. For Non-Yanmar part, an owner has said that they have used it and it works. If you find more accurate information, please send me the information and I may edit this post.

Oil Filter
Yanmar part #: YAN165000-69520, or
Mann Filter #HU722Z or HU7029Z (next version). Can be purchased/ordered from NAPA parts stores for $18. [Note: This filter does NOT come with the replacement O-rings that will fit the BMW canister assembly. Have used the same O-rings for two oil changes when checked for no signs of wear.]

Fuel Filter
Mann WK1150/2

Fuel Water Separating Filter
Racor S3204TUL
Baldwin BF46028-0
 
j&lgray":nr85motb said:
Fuel Filter
Mann WK1150/2
Click to expand...
I have tried this filter on my 4BY2 powered 2012 R27. It does not fit because it is an inch or so too long and it can’t be positioned properly to thread into place. Other 4BY2 owners have reported the same problem. I understand that it DOES fit on the 6BY engines.
 
Topic: Mann Fuel Filter
Summary: Two owners of the 4BY-180 are using the Mann filter as listed after minor modifications to the mounting bracket.
Here is a link to a supply source from a tug owner: https://www.dieselfiltersonline.com/wk- ... k1150.html

Topic: Seawater Pump Drive Belt
OEM part is Hutchinson Flexonic Poly V, PK964. My experience is this specific belt is the best, maybe only, solution because this is a stretch belt.

Question: Are you using another belt?
Question: I am not finding this belt for purchase, where are you getting it?

The Yanmar part number for this belt is 120650-42360 and sources were easily found but this is not a Flexonic Poly V belt. I know, I bought this belt and though it is the same size in every way, it does not stretch easily. I have not forced this one on because it was difficult. Update edit: I have talked to the experts at Yanmar's Mastry Engine Services and they are doing research to verify that their replacement belt is the correct one. My experience on this subject is that many people in the industry do not know about stretch belts. The Yanmar part number provided goes to a Bando Ace Fit belt that has the same specs as the Hutchinson belt. According to their website, It is designed to be stretched and the manufacturer says to use an installation tool. Info on the installation tools use the technique of turning the crankshaft with ratchet and socket.

Question: Do you have another experience?

You do not have to post a reply here. You can PM me or email me at johnlgray425@gmail.com. I will post the results of this research on this thread.
 
Hi,

On our 2011 R27 with Yanmar 4BY2-180, I replaced the belt on my raw water pump. The local Yanmar dealer supplied me with a Bando Rib Ace 4PK964F which fit perfectly. Initially, they handed me a 4PK965F which was so loose I could 'stretch' it into place with just my fingers.

When I replaced the raw water pump impeller two years ago, I used the o-ring supplied with the impeller. This o-ring was just a little too small to want to stay in the groove on the face of the pump housing. This made it very challenging to put the drive/bearing housing back in place before the o-ring hopped out of the groove. After finally getting it into place, I started some research on finding the correct o-ring.

Today when I replaced the impeller again, I used the 'right' o-ring. This was a #038 size, shore A 70 hardness, available from Grainger for $1.38/10 parts. It slipped right into the groove and stayed put.

stay safe,
Brendan
 
I found using a small dab of Permatex gasket sealer holds it in place. Quite frankly I have only replaced mine once.
 
WARNING
I tried to connect to the web site listed above (Yanmar Parts Catalog) and my McAfee Total Protection program went “nuts”. Certificate error – warning that files will be deleted, possible data “theft” and so on.
 
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