Which Yanmar water pump?

Nov 2, 2016
51
Hunter 27 2 Rock hall MD
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I have a 1978 Hunter 27 with the Yanmar engine and I need to replace the gaskets and the impeller on the cold water pump. How do I know if the engine is a YSE8 or B8 and does anyone have a part number for the water pump or seals. See pics attached
 
May 29, 2018
457
Canel 25 foot Shiogama, japan
There should be a brass name plate on the top of the flywheel housing which identifies your engine..
Stick your head over the engine and take a look.
Sometimes they are corroded or missing.
Your photo is of a direct drive pump, both Yanmar YSE 8 and YSB 8 have belt driven water pumps.
You have something else.
The impellers and gaskets are pretty standard (see the attached address) and you can make you own gasket from copy paper or old chart paper.
https://www.marinedieselparts.com/store/yanmarpumps_ysb8.htm

gary
 
Nov 2, 2016
51
Hunter 27 2 Rock hall MD
This is super helpful, i really aporeciate it. i replaced the impellar with a spare that i had on the boat but the bypass seal has allowes water in the boat twice this month so im looking for the exact kit to replace the omd one. Im headed to the boat on Thursday so ill look for tge plat then but i really dont recall evwr seeing one.
 
May 29, 2018
457
Canel 25 foot Shiogama, japan
Hi Jon
I take it from your reply that your pump is leaking between the face plate and the body (the bypass seal has allowes water in the boat twice this month).
The pumps can leak from there or from the shaft seal.
The face plate and body can have small scratches which make it difficult to seal even with a new gasket.
But they can easily(and cheaply) be fixed by lapping on a sheet of glass using valve grinding paste. Only lap as much as needed. The bronze is pretty soft and will grind away quickly.
https://www.bing.com/videos/search?...DE20D26D4BD216B44C75DE20D26D4BD2&&FORM=VRDGAR

You can also completely recondition the pump.
https://pbase.com/mainecruising/raw_water_pump
1. Remove and disassemble.
2. Leave bronze parts to soak in vinegar.
3. Lap face and body.
4. Fit new seals and reassemble.
No special tools needed and an as new pump. About 4 hours of satisfying work.
You will also need a new pump to crankcase gasket
gary
 
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Nov 2, 2016
51
Hunter 27 2 Rock hall MD
Thank you Gary and I’m sorry for the late reply. I had to transfer to a new phone and reset all my passwords. Ugh! Well my story of woe just got worse. I did install a new rubber ring and gasket to the water pump, checked or replaced hoses as necessary but after a few minute of running the engine, the by pass occurs and I have water pouring in from the bottom of the pump. To make matters worse, I also have diesel mixed in with the water some how. Bad rings? Thoughts?
 
May 29, 2018
457
Canel 25 foot Shiogama, japan
Jon.
Before anything else,we need to know what model your engine is.
Heritage could be correct that it is a 1GM10 but could you confirm that?
Do you have a manual?
Also some of your explanations seem a bit strange.

"but after a few minute of running the engine, the by pass occurs and I have water pouring in from the bottom of the pump."
I don't what "the by pass occurs" means. can you explain that more clearly.

Also, "water pouring in from the bottom of the pump".
Do you mean from the bottom of the face plate or the bottom of where the pump is attached to the engine.
Either way, even though you have replaced the rubber o ring and gasket you obviously still haven't fixed the original leak. So, off with pump and repair it properly.
Lastly, I also have diesel mixed in with the water some how. Bad rings? Thoughts?
I don't understand this at all. Are you saying that the diesel is mixed with the water that is leaking from your water pump.
I would say that is pretty well impossible. Bad rings would have no relation to something like that.
Rings are in the pistons and seal the cylinder (bore). That seal gives you compression and keeps the oil from entering the top of the cylinder (combustion chamber) and being burnt.
bad rings mean, poor starting, lack of power and burning of oil. A whole different ball game from a leaking water pump.
Please get back to me with answers to my questions and we will work this out.

gary
 
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Jun 8, 2004
10,024
-na -NA Anywhere USA
@Jon Elliott
I believe the old style Hunter was built between 1978-1984. It contains the 1GM model Yanmar which is about a 7.6 hp engine while the 1GM10 is a 9 hp but the manual on line for Yanmar will work for both.
The dealer for your area is Mack Boring and Parts Co.
I just fixed a 1 gm on a 1981 Hunter.
Do you have the original water separator as it will be solid metal? If so I suggest replacing it with the clear bowl on the bottom so you can see. In addition you will have to I suspect replace the hand pump as it needs to being 41 years old. Here are some numbers for you:
Item Model number
Fuel/water separator 370-4120
Fuel filter element (GM/HM engines) 370-104500-55710
Filter assembly 370-119305-35170
O ring (fuel filter) 370-24341-000440
Hand pump 370-105582-52010 (order gasket)
Impeller kit (ask if gasket is included) 370-128176-42080 (if not order separately)

The hand pump does not come with the gasket so order it. Check if impellor kit contains the gasket. Replace lines from gas tank and thru the system. Do not disconnect line that attaches at the injector. Remember this is metric, so have both standard and metric tools.
do not take the fuel shut off from tank as that will be a bear to do so.

Contact info for your area dealer is:
Mack Boring
245 Belmont Drive
Somerset, NJ
908-964-0700

Send me a private email stating H 27, 1978 model/1GM engine with you phone number and I will discuss what I did.

Crazy dave
 
Nov 2, 2016
51
Hunter 27 2 Rock hall MD
@Crazy Dave Condon. Your above post is starting to turn on a light bulb in my head about some of my possible issues. Particularly the fuel water separator. I’m going to reach out to you privately but I wanted to lay down some food for thought for the entire thread participants:

First, I did find the plack to my engine the other day and it is indeed an SB8 (see attached) But, my pump is a bit different than the 1GM10 pumps I’ve seen in videos. Mine has a round impeller cover while others have a triangular shaped one. Perhaps mine is just a very early version but mine also has a second snap ring in between the water seal and oil seal. The 1GM10 rebuild kit I ordered from Poseidon only has one seal so I’m not sure if they got it wrong or I have an odd ball pump.

Second, I don’t see a hand pump on my motor and I’m not sure I’m following your instructions well enough to understand it’s use. More on that in a private message.

Lastly, (and sorry for the newbie Diesel questions) is the Fuel/ water separator the same as the fuel filter? If so, the bottom of mine is clear.
 

Attachments

Nov 2, 2016
51
Hunter 27 2 Rock hall MD
@garymalmgren Thanks for your help Gary. I know my post is probably quite confusing. As understand the pump and it’s function, if there’s too much back pressure down stream, the seal will move and allow water to be diverted out of a rectangular shaped hole at the base, which keeps the water from going into the engine case on direct drive pumps. Newer pumps with an external belt/ pulley may not need this. So, after a few minutes of running the engine, it will start to drip out of the bottom of this rectangular hole, then start to gush out, providing no water to the engine. I did remove all but the very last piece of my exhaust system and either replaced or cleaned out each piece to make sure I had sufficient flow and no back pressure on the exhaust/ water cooling lines. Since I wrote my last message, I had the pump apart again and found one of the seals not in place. Put it back together and again, after about 5 minutes I have water pouring in from the base of the pump (rectangular opening). The diesel smell is a different matter. It does not appear to be coming from the pump or the lines but the pan beneath the pump that holds the stuffing box drip and grime was full of diesel and water. Even though I had just cleaned it out a few days prior. The good news is, the engine runs well, I have plenary of power (for an 8hp 40 year old motor) but this pump issue is really driving me crazy and I have no idea where the diesel can in at. No apparent leaks on the fuel lines any where. The search continues.
 
Jun 8, 2004
10,024
-na -NA Anywhere USA
I have never seen nor worked on that engine. It is an engine that was built and shipped in the 1970's. It is a flathead engine and some parts are still available thru your local dealer, Mack Boring located in Somerset, NJ whose number is 908-964-0700. Press 1 and ask for Michael or Jim. It would be helpful that you state the model is SB8 and serial number.. It is different than the 1GM/1GM10.
If the original fuel/water separator which separates the water from the diesel you may want to consider replacing it with the one listed as it has a clear bowl in it to detect water in the fuel. On the 1GM/1GM10, there is a separate fuel filter with O ring
Give me a call and I will give you addl. information.
Crazy Dave
 
May 29, 2018
457
Canel 25 foot Shiogama, japan
Hi Jon
I am not familiar with the SB. it seems to have been a fore runner of the GM series.
From your description (is that information from a manual or did someone tell you that?)
if there’s too much back pressure down stream, the seal will move and allow water to be diverted out of a rectangular shaped hole at the base, it looks like there is a restriction down stream.
In your photo of the old impeller, half a blade is missing, has this by any chance lodged in the discharge hose from the water pump and caused e restriction? Or have you fished it out?
I would disconnect the discharge hose from the pump place bucket to catch the water and run the engine for a few minutes.Then you will know if the pump is delivering.
Next connect the hose to the pump but disconnect it from where it enters the engine. Run engine and check the hose is not blocked.
Next remove the water exit hose from the engine (it runs to the exhaust pipe water inlet port), Run engine and check flow.
If there is a reduction in flow at any point along the way. check it out.
You will get away with running the engine with no cooling for a few minutes at a time.
When you smell burning exhaust hose rubber you have gone too far.

keep us filled in on your journey.

All the best
Gary
 
Nov 2, 2016
51
Hunter 27 2 Rock hall MD
@garymalmgren Thank you for the follow up Gary. I have replaced the hoses to and from the water pump to the engine, and removed and inspected the exhaust hoses from the engine (metal exhaust bend) to the “muffler” and found a great deal of charred pieces in the muffler. The only piece I’ve not inspected or replaced yet, is the last piece of exhaust hose from the muffler to the discharge point in the back of the boat. I do have suspicions about that piece of exhaust but at the time, it was too difficult to remove before I had to head home. That’s my project for next week. With the help of some great people on this thread, I have some contact help and a new path for rebuilding the pump again, so I’m hoping for success in the next few weeks. I do plan to document and share what I find as I go along.

Once I’ve determined those exhaust lines are clear, I’ll run water through as you described above to verify it’s flowing properly. Thank you again for all your support and patient guidance.

Jon
 
May 29, 2018
457
Canel 25 foot Shiogama, japan
Hi Jon
You are doing everything the right way, so you will beat it in the end.
Hang in there. As they say,"It is a learning experience."

gary
 
Nov 2, 2016
51
Hunter 27 2 Rock hall MD
@garymalmgren. I hope you’re right. I know my way around a car engine fairly well but diesel brings a whole new set of challenges and understanding to the tool box. I’m taking my time because I do want to do it right but man, I’ve lost a lot of the sailing season, particularly because I commute to the boat. Alas, boat ownership.