Mack Boring Yanmar BY series maintenance workshop

HRowland

HRowland

Well-known member
Joined
Feb 28, 2011
Messages
463
Fluid Motion Model
C-24 C
Non-Fluid Motion Model
2008 Nordic Tug 37
Vessel Name
Catnip
MMSI Number
368024230
Learn WELL how to change the raw water impeller - in your sleep.
Then insist that they lay a blanket over the engine and clamp a board in your way so you can practice doing it laying on your belly, on top of and from behind the engine, blindfolded, and with your arm bent at an impossible angle.
Don't believe me? Go to your boat and look at the impeller.
Oh wait - that's right, you can't see it. 😉

I thought the impeller on my Cummins was bad until I saw one changed on the Yanmar.

denny-o
 
I have a commitment that week otherwise I would be interested in attending.

As far as getting to the raw water pump I have the R25SC (2010, brand new to me with 88 hours). I wanted to check on the condition of the impeller before the season begins.
I removed the panel on the port side of the step, completely removed the access hatch on the front of the step. Remove all the screws from the board separating the engine compartment, also remove the aluminum bracket supporting the middle of the board (otherwise it will cut up your arms). This board will now slide into the cave. It's a tight fit but I was able to squeeze into the step to work on the pump.
Following the directions that Knotflying posted ( viewtopic.php?f=5&t=3318&p=24345#p24333 ) I changed out the impeller by myself.
Before I ever do this again I will modify the opening on the step. That hole can easily be enlarged by a couple of inches or more length wise and maybe an inch or so top and bottom and a hinged teak door made for the new opening.
By the way my impeller was in bad shape, one vane completely off, two others were split, luckily the missing vane was in one piece and still in the pump housing.
 
Howard, enjoy the class and write down in advance all the questions you may have and all you want to see. Larry, the instructor is very knowledgeable, but can go off topic at times, so don't be bashful to reel him in, you want to get the most out of the class. John Decaro and I were lucky, we were the only two in the class because everyone canceled because of the hurricane Sandy aftermath so our class was a one on one. I also took pictures of the engine since it was not in a boat. I now have views of things you need to feel your way through in real life. I found pulling the impeller out and seeing how the serpentine belt goes on very helpful. Learning how systems work will help if problems arise down the road.

Mike Rizzo
 
The class is only one week away, I am looking forward to it. Any other TugNuts going?

Howard
 
Howard,
When Mike and I were finished he asked me what I thought of the class. I must say I walked away with almost no fear of tackling the routine service that is required on a periodic basis. With everything being controlled by the electronics there are areas that we will never be able to work on. As Mike said, Larry is a very knowledgeable man so have all your boat engine questions ready. I also bought the Yanmar service/shop manual at the parts counter on the first floor. It's a full day so take notes.
John DeCaro
 
Know Your boat!

After our experience with a lightning strike, we decided to learn as much about the 6BY2-260 as possible. We have studied the Yanmar wiring diagrams around the ECU and damn near memorized them. The four and six cylinder BY's function in generally the same manner. Don't hesitate to ask at the class what the engine will run without and how it responds to certain component failures. This info is contained in the engine users manual but it helps to understand the emergency features that will get you home, slower maybe, but at least not left in open water with no power. It will run without the fuel rail pressure sensor. The computer just uses a default value and limits power output. It will run without the camshaft speed sensor but will be hard to start. It won't run without the crankshaft speed sensor. We went through all of these before we found that we had an analog throttle with two senders, one of which was partially grounded. I know this is not "routine" maintenance stuff but it is good to know. Our final bill for repair was over $20K but the lessons learned were priceless!

Pat & Carolyn, Ladybug, Too
 
Thanks for the tips everyone. Should be an interesting day!

Howard
 
This was a good class. It was nice to be able to walk around a BY2 engine and take a few pictures! We got a chance to change the impeller which was a useful experiment. A few interesting points (note they are conservative and base this on Yanmar instructions)-

1. The engine coolant block drain is behind the heat exchanger. The service manual says to remove the heat exchanger so you can drain the block. Yanmar states a 2 year/500 hour interval (whichever comes first) between coolant changes so mine is now due based on 2 years. Has anyone done this? (other than the unplanned ones due to the heater hose failures!)

2. The service recomendations state replacing the turbo heat shield every year/250 hours. I asked the service manager about this. He said that the insulation deteriorates and reduces the heat shielding capability. Has anyone bothered to do this?

3. Air filter- they do not advise cleaning it and want it replaced. I questioned this and the instructor said he has to state the official Yanmar policy. I had good results cleaning mine last year using a K&N kit, based on the dirt removed at about 125 hours I plan to make this a 100 hour action item.

4. Turbo Wash- They suggest every couple of years to keep the turbo compressor vanes and charge air cooler clean. This is a multiperson job, it needs to be done at high power under load. He suggested having it done the first time to watch how it is done then do it yourself the next time. If too much cleaner is put it at once you risk hydraulic lock in a cylinder with a lot of expensive damage.

5. The engine thermostat starts to open at 190F. It is fully open at 205F. When we see cruise temps of 201-202 or so the thermostat probably has not opened fully yet!

6. Impeller- Change every year. Clean the bore with a Scoth-Brite pad. You can use Petroleum Jelly to hold the new O-ring in place. Use dish soap to lubricate the new impeller during installation. Be careful when working the belt off of the pump pully, it can crack (tip from the service manager). A flat tool is best, the instructor has a ground down screwdriver that he uses. The official line is to use the Yanmar tool.

7. Expect about a 5 year lifetime for the exhaust mixing elbow.

Howard
 
Howard,
I think some of Yanmar's periodic maintenance items are overkill. As far as the antifreeze goes I just changed mine, but did not remove the heat exchanger. I drained the overflow and drained from the petcock, which gets about half the antifreeze out. Dex-cool antifreeze, according to the manufacturers, is good for 5 years. My approach is to drain off what ever I can and change it every year. I think fooling around removing the heat exchanger every two years is looking for trouble and a violation of "if it works don't fix it". By the way during my antifreeze change I noticed the level was a bit low. I checked for leaks on the hoses and also removed the helm heater. It looked like the clamps were a bit loose on the heater and there were signs of some antifreeze below it. I would recommend a check of these clamps as a periodic maintenance item.
Mike Rizzo
 
Hi Mike,

That is a reasonable method. From what I understand the anti-freeze properties do not wear out, only the additive package (anti corrosion, pump lubricant, etc.) break down in coolant. As long as the color is still good a partial yearly change should be good. I will do this.

Mack Boring also recomended using Dex-cool, I was surprised they did not push Yanmar coolant!

Did you capture the drained coolant? My boat is in the water now so I would not want to pump ethylene glycol overboard via the bilge pump.

Thanks for the tip on the heater connection, I will check these.

Howard
 
Howard:

Thanks for the feedback from attending the Yanmar class.

With reference to...

2. The service recomendations state replacing the turbo heat shield every year/250 hours. I asked the service manager about this. He said that the insulation deteriorates and reduces the heat shielding capability. Has anyone bothered to do this?

I also wondered about this when our 250 hr service was done last Sept. Where on earth is that "insulation" ? All I can see is the shiny SS (presumably) heat shield. Is there 'unseen' insulation on the underneath of this shield ? If Yanmar is serious about this as presumably the turbo housing can in fact glow dull red when running the engine hard, they need to make replacing this heat shield more obvious in the manual.

Our Yanmar technician did not advise changing the heat shield when I pointed him to it's replacement schedule.. 😉 😉 😉
 
Mack Boring also recomended using Dex-cool, I was surprised they did not push Yanmar coolant!

Did you capture the drained coolant? My boat is in the water now so I would not want to pump ethylene glycol overboard via the bilge pump.
Click to expand...

I bought a little 12 volt self priming pump from Harbor Freight and an 8 foot washing machine hose that I cut into 2 pieces, 6 foot and 2 foot. I was able to fit the cut end of the long hose over the petcock. I connected the pump with alligator clamps to the starter wire and grounded to the engine and pumped it into gallon jugs. It worked well, not a drop in the bilge.

As far as the coolant goes. I did extensive research on this. I even called Havoline, one of the recommended products. It turns out that the specs are all Asian numbers and they are really referring to Dex-cool. So when I asked the Havoline rep, "isn't Dex-Cool the same no matter who makes it?" After a pause the response was yes. So I bought Prestone, full strength and mixed it 50/50 with distilled water.
 
I checked out the underside of the shiny SS turbo's heat shield and did find there's heat insulation there. It's difficult to nigh impossible to determine if it has deteriorated and needing to be replaced. To get at the insulation to see what condition it's in one would need to remove the complete heat shield -- which actually looks quite straight forward as I saw 2 or maybe 3 bolts holding it in position.

Does Yanmar say to replace just the heat insulation or the insulation and SS shiny metal cover as an integral piece ? Maybe the heat shield + insulation comes ONLY as one piece and if so that's overkill for sure as the SS shiny cover on my Yanmar 4BY2-150 looks pristine.
 
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