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Yanmar fresh water cooling pump

BJoslin

Member
Good evening all,
Developed a coolant leak on the cooling water pump. I foolishly thought that this was going to be a fairly simple fix. Quick internet search and I was able to purchase new mechanical seal and gasket so I began pulling the old pump apart following the service manual. When I started to pull the impeller it crumbled with very little force. And here is where I am running into issues. I am having no luck finding a replacement impeller(124250-42200). Also not finding a replacement pump assembly (721390-43700).
Any chance any of you who have replaced the Yanmar are holding a gold mine of spare parts? Or any leads on replacement parts?

Thank you,
Barry
 
Barry
There are no pump bodies available any longer for the 3QM30. Anywhere, I've searched. The bushings and gaskets and impellers should be still around. Tomorrow I will search my records to find the stock numbers for those. A machinist told me once that when the seals no longer do their job, to bring him the pump and he would make a new shaft for it.

Jim
 
Thank you Jim. Any help

In case I am unable to get the right part I was brainstorming other possible solutions to keep the old beast running. What is everyone’s thought on using a belt driven raw water type pump in place of the stock fresh water pump? I would have to fabricate mounts for the pump and ensure belt alignment. But my real concern is flow rate and pressure. Not sure if the two types of pumps are similar in those areas. What do you all think?

here is a picture that I found on here that led to that idea. 9F6A8880-D8E6-4A0E-82B2-FBE118D96EC2.png
 
Barry
Here are the numbers I have for the salt water pump parts:
Salt water impeller: 145410-46050
Salt water impeller (Bilge) 145410-46091
Salt water pump Gasket: 145410-46110
Salt water pump seal: 24421-173208
One thing about Yanmar that drives me nuts is that they change their numbering system from time to time. So these numbers may be changed to new numbers. Go figure???

I have heard of owners using after market pumps such as Jabsco pumps. I have not heard about difficulties with flow rates connected with those pumps. I have changed the seals on mine twice now and keep two sets on board at the ready. When the seals no longer stop the leaking, I'll have the shaft remade.

Jim
 
Jim,
Thank you for looking those up, I will definitely save those numbers. I do need to order a couple more spares.
Unfortunately that is for the raw water pump and what I am looking for is the belt driven fresh water(coolant) pump. #5 in this parts diagram.

Thanks again,
Barry
 

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Here is a picture of the back side of the pump and my broken impeller
 

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Barry
I made a mistake. When you wrote cooling water pump, I thought you were talking about the salt water pump feeding to the heat exchanger. Your photo shows the fresh water pump. Those numbers I gave you are for the salt water pump. I'm sorry. I have not had an issue with the fresh water pump to be of help to you.

Jim
 
That’s alright Jim. I still appreciate the info, it will be helpful when I order those spares. Thanks again
 
One last question before I decide what I want to do with this old Yanmar. Still have not been able to locate a replacement impeller for the fresh water pump. Attached is a picture of the backside of pump and impeller. Also a pic of where the pump mounts on the engine. You can see a small hole just below the top mounting bolt hole on the engine. Any ideas on the purpose of this hole? Only option I have come up with for salvaging this engine is to come up with an alternative to the stock fresh water pump. And mount a blank plate over where the factory pump would go. But I have not been able to figure out the purpose of that hole and possible issues I would run into with blocking it off.
 

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I have the same motor and took a look at the back side of the pump body bracket. I'd bet the hole is a breather so the pump can't get airlocked and leads to the chamber where the temperature sensor lives.

As for the impeller... Have you tried discount marine source? They say the have it for $50 + $10 s&h.
 
Nth,
Thanks for the info. So I guess blocking it off might not be the best route to go.

I think this might be one of the companies I have already tried. There were a few that showed it on their websites but don’t actually have it and can’t get it. I tried calling with no luck so emailed them to check availability. I’ll let you know when I here back. Fingers crossed.

Barry
 
Here’s what I got back from Discount Marine.

Thank you for your inquiry. Unfortunately we do not have part 124250-42200 in stock in our warehouse. It has also been discontinued with no replacement. I would suggest possibly trying eBay and see if you can find a used one if you haven't done so already.
 
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