Sea Water Impeller Replacement for the Yanmars

J

j&lgray

Well-known member
Joined
Nov 28, 2008
Messages
644
Fluid Motion Model
C-28
Vessel Name
Trilogy
Being a good rule follower, today I replaced the sea water pump's impeller. If you have a Yanmar 110 HP engine, the owner's manual says in one place to replace this impeller every year while in another place, the manual says to replace it after a 1000 engine hours.

My trusted marine mechanic told me to replace the impeller at the start of every boating season because this little neoprene, bladed impeller will stop a trip cold should it fail. If you did not know, this impeller sucks seawater into the engine's heat exchanger to cool the engine coolant and then it pushes the sea water out through the exhaust. Should it fail, your engine will quickly overheat. The quickest way to lose an impeller is to run the engine with the sea water intake closed. I did that twice by mistake. Typically, in just a few seconds without seawater, the impeller will break a part. According to the boating guru's, replacing this impeller is one thing that every tug captain should be able to do on the water. That means your have to carry a spare one and have an idea how to do it.

If you have not done it, it is very straight forward and the owner's manual only gives you the barest of information. You will need a metric socket on a short handle, the quarter inch drive works very well. The four bolts that hold the pump cover on are the same size as the hose clamps used throughout the tug. I have marked that socket with red tape because I need it more frequently than the other sockets. These small stainless bolts come out easily, but because they are 5 mm heads and short, you can lose one easily in the bilge. So, I went to the hardware store and got three extra ones at 27 cents a piece and put them in my spare parts bag.

When you got your tug, you likely got the impeller extraction tool. I did not know that I had one until I saw the diagram of the tool in the manual and my mechanic told me that the tool comes with the engine. Low and behold, in the Ranger bag of manuals and parts, was the impeller extractor tool. Simply thread the larger part into the end of the impeller and thread smaller bolt into it and it gently and quickly takes out the impeller. Sure beat the old method with two flat bladed screw drivers and prying it out!

The original impeller is a Johnson pump part, number 1027 BT. The "T" in this part number means that it has some really neat threads in the center and at the end for a very handy way to easily extract the impeller. I have not been able to locate this impeller with the threads. Everyone sells the 1027 B for about $25 but not even the Johnson Pump company website lists the 1027 BT. Even the local Yanmar dealer sells an impeller, for $40, that does not have the same number of blades as the Johnson and it does not have the cute threads in the end.

Faced with no choice but to use the unthreaded one, I got the 1027 B impeller. Next, put some marine grease on the shaft and on the impeller blades. DO NOT use a grease that is petroleum based because it does not react well with the neoprene. I use Superlube, a synthetic based lube for the trailer and this or a lithium or aluminum based grease will work nicely. Rotate the impeller counterclockwise into the pump housing and this bends the blades of the impeller to the correct direction for pumping. If you put this in wrong, the blades will likely immediately fail, when the pump starts, so you have to get this right. The owner's manual shows the correct way. The blades at the top of the impeller bend down even more in the housing. The impeller just slides in with hand pressure.

Replace the O-ring that keeps water from escaping through the cover plate. Oh, you need to carry a spare one those too.
Put a little grease on the O-ring and press into the groove in the pump housing. Put on the cover plate and gently snug down the four bolts and your are done.

The hard part of this job? Getting to the pump housing. It is on the port side of the engine, toward the forward half and toward the bottom of the engine. I had to stand on the starboard side of the engine, lay across the top of the engine, and stick my head and arms down the engine's the port side. A folding inspection mirror with a flash light located the cover plate quickly. Then it was all by feel and quick glances. For my first time in replacing this impeller, the job took about 20 minutes. Next time, I could it in 15 minutes easily.
 
About the same thing for the 21 foot boat. Six screws and the cover is removed. Good idea to plug
the hole in the engine belly pan with a piece of duct tape if you drop a screw. Johnson part is a lot less
costly than Yanmar part. Mine was bad when checked at the 50 hour service. Motor did not overheat
in December and was shy one vane. Good time to also think about the belt that drives the pump.
Bob Heselberg Eatonville Wa
 
😀 JOHN, [AND LAURIE TOO, OF COURSE] JUST WANTED TO THANK YOU FOR THAT VERY INFORMATIVE IMPELLOR POST. I KNEW IF I WAITED LONG ENOUGH, I WOULDN'T HAVE TO ASK ANY STUPID QUESTIONS... HAVING BOUGHT HULL 15 ON USED MARKET, I HAVE NO GENERAL MANUAL, EXCEPT FOR THE YANMAR ENGINE , AND OF COURSE MANUALS FOR EVERY OTHER SYSTEM IN THE BOAT... ARE THE INSTRUCTIONS IN THE YANMAR BOOK. WILL BE PULLING THE CHRISTINA BEE OUT OF HER MARINA FRIDAY. WOULD WEST MARINE HAVE AN IMPELLER?? THANKS AGAIN, STEVE AND TINA, WE GOT NO CLUE
 
Steve, the West Marine web site says that the Johnson 1027 B impeller is in stock. Now, whether an individual store has it, is worthy of a phone call. Always feel free to ask me, or anyone else for info, we are all learning, all the time.
 
Thank you! Good post, informative and maybe life saving too.

Dave
"Lobo"
 
I pulled the impeller on Island Ranger yesterday - (R-25) - just because the manual says it should be replaced every 1000 hours and I was getting close (have 800+). I've been giving it a visula inspection a couple times, but this time I pulled it completely. It was in fine shape. The impeller removal tool worked like a champ.

When I went to install the replacement impeller - I too discovered the absence of threads (and different number of vanes). I figure it will be a pain to remove without the threads, so I decided to put the old impeller back in and start the search for the correct part. I talked with my yanmar guy today - he has not been successful so far, but is trying.

If anyone finds a source of the threaded version - please let us all know -

Thanks,

Mac
 
I talked with Jerry at Jim's L&M Marine (Yanmar - Everett). He says that after ~10+ phone calls, he found out that Yanmar is trying to use up the old inventory (no threads, etc) and are holding back the new ones. He succeeded in getting part number for the new impeller- apparantly they have some in Chicago. He is hoping they will arrive here later this week.

Am keeping my fingers crossed.....

Mac
 
I went to the source of the Johnson impeller that was the original equipment. Johnson Pump is a corporation based in Sweden and I contacted the North American representative. He was very responsive and determined that Johnson Pump had not imported the Model 1027 BT (emphasis added) impellers into the states but were sold to Yanmar in Japan and Yanmar in Europe through its office in the Netherlands. When our engines were made in Japan, they were installed with these impellers.

His email to me, "Here is the answer I received from Europe. It appears that this impeller is sold to Yanmar in the Netherlands and to Yanmar Japan. The Yanmar part number is included in the response. We have never sold this item as an aftermarket part here in the US. You may try reaching Yanmar in the Netherlands or Japan to see if the impeller is available from one of their Yanmar dealers in Europe."

The response that he got from the corporate office was, "This impeller is sold to Yanmar Europe, The Netherlands = spare part handling and to Yanmar Japan. They buy the 08-1027BT impeller and likely make a kit themselves. We do not have a 09-1027BT. The Yanmar part number 129670-42531 might therefore not be the ones used for sale to end customers.
If this one is sold to US it is via Yanmar in the Netherlands. (Note that the Yanmar number may be a production part number and not necessarily a part number familiar to the aftermarket dealer. You may want to give the number to the Yanmar parts group in Buffalo Grove, Illinois. Perhaps they can run the part down through the Yanmar network.)"

That is what I know for now. My suggestion, while waiting to see if we can get the impellers sold in Japan and the Netherlands, get the 1027 B impeller from Johnson because the Yanmar impeller has fewer blades on it and therefore is probably more effective at pumping water and is definitely cheaper.
 
Thanks John! Great info....have you talked with WM and or ordered parts?????

Drew
 
Quick question for the impellor experts.

Would it be possible to access the impellor on the R 25 by taking the step (from cockpit to cabin) apart...there are four screws there and it would appear that that would give you some access to the part on the engine.

tom
 
Access to the water pump housing cover is easiest from the stern. The small bolts face that way. I found it easiest to hang over the cockpit door threshhold - but John liked draping himself over the engine. The four bolts (8 mm socket) were pretty easy to remove. I'd recommend using a mirror to get yourself oriented first

mac
 
I'm just about done completing this (I forgot to stock up on grease before I started, so the new impeller is ready to go in - which should be the easy part). John's original posting was certainly helpful in preparing me for what I was in for. This should be a fairly straightforward maintenance task, but due to the position of the engine (at least the 4JH3) it's a bear. It certainly took me more than 20 minutes, but then I didn't start with a threaded impeller and puller. I had to get a pair of needle-nose pliers onto the blades of the impeller and work it out a little at a time. Try doing that leaning upside down and backwards over the engine, with precious little space between the water pump and the starter.

It did seem to me that it might be worthwhile to just remove the starter motor before attempting this. It would open things up to get the tools in and significantly improve visibility. It would help even more if a source can be found for the threaded impellers (and the pullers, please). I'm wondering if a small bearing puller couldn't be adapted for this purpose. I.e., the tongs would have to go in between the blades of the impeller and catch on it near the back end, and then it could be "pulled" by tightening down the screw. Thoughts? I don't really want to have to go through this exercise next year without coming up with a better process.
 
Two brief additions to my post. First of all, when I went to WM to get some grease, the guy mentioned that he had just looked up an impeller puller tool for someone. He showed me in the catalog, it looks very much like a bearing puller. They have a large and a small size. Both cost close to $100, so my Scottish nature got the best of me and I decided to wait until next year.

Secondly, I put my impeller back in, twisting the blades so it would turn counterclockwise - which is what John said above and I'm quite sure the way they were when I took it out. Then is double-checked in the operations manual, and it says exactly the opposite: the motor turns counterclockwise, but you should twist the impeller clockwise. I've already run the engine for 5 minutes or so and it didn't heat up at all, so I don't appear to have destroyed the impeller. But now I'm not sure whether I should just leave it alone, or at least open it up again and inspect it as best I can.
 
Humm..

Which engine do you have? On our 4HTE - the 110 Hp Yanmar, pulling the impeller (when it has the threads) is really easy. I didn't think the starter (where is it?) ever got in the way...

I might have a spare " impeller puller" that found its way on Island Ranger......

Where are you in BC?


Oh, and an update from my Yanmar mechanic.... still waiting for UPS to deliver the impellers....

Mac
 
One word...... mechanics...... If I do their job, they won't have one..... I know, we should all be self sufficient..... never been one to change my own oil..... again, mechanics.....
 
To Island Ranger:

I'm in West Vancouver. I have a Yanmar 125 (4JH3-DTE). I haven't seen the 110, but even though they have the same block, I'm inferring from the posts here that the other components and the installation in the Ranger are somewhat different. My impeller is not threaded, so the puller wouldn't help. It's back in anyway, and if I find that I damaged it I have a spare. But thanks for the offer.

To Solitude:

I also appreciate the value of a good mechanic. Part of the reason I have a boat is because I like doing things like this myself. I don't do these kinds of repairs on my truck, for instance. But I also cruise in many places where help is not available. Things break down, and part of my discipline as a prudent mariner is to be able to fix them myself when they do. I don't want to have an impeller blow up out in the middle of nowhere (which can easily happen if something gets through the raw water strainer), and find myself without the tools, parts, and basic knowledge required to make a repair myself. I appreciate that this is not everybody's cup of tea, or even necessary for many people. Each to his or her own.
 
Ram,
In five years when we untie the dock lines, cast them ashore and head off on the big adventure, I (hope) will be prepared to undertake such tasks. At this time due to our jobs (theres that nasty word), we are limited to cruises that keep us close to the folks that can assist us with such matters.

We are not the types that would set off with an EPIRB, get into trouble in a big storm, and expect another to come rescue us at risk to themselve. When you set out on a large ocean or bay, you must be able to take care of yourself. You cannot ask another to risk life and limb to assist you because you made a bad decission.

I am jealous of those that can do these things themselves. However, with the limited amount of time that we have each week to enjoy our boat(s), I would prefer to have the local dealer do the "preventative maintance" necessary so as to not take up our limited time. As the time to shove off approaches, we will prepare ourselves to be self sufficient.

Steady winds and following seas to you and yours!
 
Hi Ram,
I rechecked my manual for the Yanmar 110 and the impeller does go in counterclockwise. I also took a digital photo of my impeller before I pulled it so I could remember and be re-assured that it went back in correctly. If your engine did not over heat, then you got it in correctly. I did find, however, through hard experience, that the engine at idle can take a few minutes before it over heats. In this story, I had closed the sea water intake valve to clean the strainer, got distracted, and then failed to open the valve after finishing the cleaning job. Started up the engine, idled a few minutes, cast off the lines and headed out into the harbor at about 1400 RPM's. We were about 5 minutes from the dock when the engine speed was increased. I now know the sound of the high temperature alarm! I knew instantly the cause of the alarm and immediately opened the valve, leaving the engine idle and circulate the 42 degree water through the heat exchanger.

I did not turn off the engine fearing that the impeller would lock up inside the pump housing. In two minutes, the engine temperature was normal. Later, I inspected the impeller and found it in great condition. The near over-heating caused other problems in the water bath exhaust system. But that is another story.

Yanmar also sells another impeller puller that is listed in the owner's manual besides the remover that came with the 110 hp engine.
 
I just picked up two impellers for my Yanmar 110 - the ones with threads. Jerry has two more left - and will get more if needed. (Jim's L&M Marine - Everett).

The key is to get the new part number 129670-42531. I paid $31.80 each. I understand Yanmar still has a bunch of the old ones, and are relunctant to supply the new part number 'till they use up their old inventory

Mac
 
Mac,

Do you have a number to contact Jerry??? I would like to get ahold of the "appropriate part" and supply in tacoma area for Yannies is difficult to say the least!

Thanks,
Drew
 
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