• Welcome to this website/forum for people interested in the Morgan 38 Sailboat. Many of our members are 'owners' of Morgan 38s, but you don't need to be an owner to Register/Join.

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
 

jimcleary

James M. Cleary
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
 

BJoslin

Member
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
 

jimcleary

James M. Cleary
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
 

BJoslin

Member
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
 

Attachments

  • E1839CF4-7DCD-42C4-B50E-DF4F03E534A7.png
    E1839CF4-7DCD-42C4-B50E-DF4F03E534A7.png
    960.9 KB · Views: 10

BJoslin

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

Attachments

  • 788C3034-2787-4060-886D-48E6D148266B.jpeg
    788C3034-2787-4060-886D-48E6D148266B.jpeg
    1.6 MB · Views: 14

jimcleary

James M. Cleary
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
 

BJoslin

Member
That’s alright Jim. I still appreciate the info, it will be helpful when I order those spares. Thanks again
 

BJoslin

Member
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.
 

Attachments

  • F7B23F72-A157-4ABF-9991-B271DF182325.jpeg
    F7B23F72-A157-4ABF-9991-B271DF182325.jpeg
    1.6 MB · Views: 5
  • 560801F8-6D2E-40C4-8606-CF52B1131B1C.jpeg
    560801F8-6D2E-40C4-8606-CF52B1131B1C.jpeg
    2 MB · Views: 5
Top