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  Topic Review (Newest First)
08-08-2009 12:00 PM
L124C For the record, the rubber I was worried about was part of the old seal. There are no rubber pieces that are part of the pump housing. Whew!!! The pump is over $400! Oh, and I did need to replace the shaft. It had what I thought was minor scoring, but Yanmar convinced me it would probably still leak, if not replaced.
07-25-2009 07:42 PM
scottyt l124c the water seal is a B%^&% to get out, mine was so gone that i thought it was perminate. you need to drive it out with a round dowel or some thing, just work you way around it while hitting it with a small hammer. if it gets c0cked in the hole it wont move
07-25-2009 06:36 PM
trantor12020 If you're referring to the rubber oil-seal, refer to step 13 of "Dis-assemble the Pump". There are no special tools required for rebuilding of the Johnson water pump. All tools used are common to an DIY'er. Socket spanner can be double as a cylinder press if use with a suitably size vice.
07-25-2009 04:28 PM

Believe it or not, I'm still working on this pump (parts delay). When I removed the seal, it was very worn. I thought part of it remained in the front of the housing and started digging it out. I'm having a difficult time removing it, and think the rubber piece I'm removing is part of the housing If so, I just bought myself a new pump! It never occurred to me that the housing might have a seal that didn't get replaced. Did your pump have a piece of rubber in the housing that remained, or is that part of the old seal (right answer )? If so, how did you get it out?
07-15-2009 01:37 PM
L124C Took the shaft to the Yanmar shop and they used a press to remove the bearings (races), and the shaft looked good (to my surprise). Don't know how everyone else was able to remove them without a press, but there was no way I was going to be able to do it!
07-13-2009 08:13 PM
Bearings were almost frozen!

I took the pump apart and couldn't pound the bearings off the shaft. I finally destroyed the bearings just to see what was holding them on. It appeared to me that the bearing race is part of the shaft (see picture). Sent the picture to the Yanmar dealer and he assured me the bearings were frozen on the shaft (hard to believe looking at them closely), and that I need a new shaft. Salt water had definitely penetrated the bearings and they were hardly turning at all (wonder how long they've been like that)! Amazingly, they did loosen up with some WD. I've had the boat three years and have never thought I had sufficient flow, but didn't overheat. Amazing! Just impellers almost brand new! Of course...I should probably replace the belt (surprized I didn't smell it!) BTW, "Trantor" sent me his instructions for servicing the pump. Most service manual writters would be envious! Nice job Trantor, and thanks!
07-03-2009 08:36 PM
Maine Sail

Originally Posted by L124C View Post
So...should it be dripping water?
No as that means the water seal (or oil seal as they are often referred to) is bad..
07-03-2009 08:33 PM
Maine Sail

Originally Posted by pegasus1457 View Post
Halekai (now Maine) --

How is it that every photo you post is of equipment in pristine and squeaky clean condition?
It looked like this when I started..

Originally Posted by pegasus1457 View Post
Does everything on your boats look like that?
Not everything but I do like to keep it in good shape..

Engine at 2900 hours...
07-03-2009 07:45 PM
Originally Posted by Maine Sail View Post
Time for a re-build. While not specific to your pump they are all fairly similar in design. This may help:

Re-building A Raw Water Pump (LINK)
Halekai (now Maine) --

How is it that every photo you post is of equipment in pristine and squeaky clean condition? Does everything on your boats look like that?

07-03-2009 12:15 PM
trantor12020 I just service the raw water cooling pump of my 2GM20F. The oil seal serves as water seal. There's another water seal which is an O-ring that is located between the oil seal and the bearing. This water seal (O-ring, number 10) can be seen at the "window". In front of the bearing there is a washer (16). All you probably need is the oil seal, water seal and perhaps the 2 bearings IF leak water do get as far as the bearing. You going to push out the bearings and shaft assembly so might as well replace the bearings. Should you remove the bearings, you should polish up the shaft. What I did is bring the oil seal, water seal, bearings, C-clips to a bearing specialist who supply me all this at non marine price. Just couple of dollars for all. I've written a Work Instruction on this repair. Give me your email address if you're interest in this WI.
Seawater Pump, Oil Seal p/n: 12x24x7-TC-NOK S$1.30 +gst
Seawater Pump, Water Seal O-Ring p/n: P12-OR-KHS S$0.10 +gst
Seawater Pump, Bearing p/n: 6201-LLU-NTN S$2.60 +gst
Seawater Pump, Bearing p/n: 6201-JRXLLU-NTN S$2.60 +gst
Seawater Pump, Circlip small p/n: A12-CIRCLIP-ADT S$0.30 +gst
Seawater Pump, Circlip big p/n: B32-CIRCLIP-ADT S$0.50 +gst

BTW, No it should not be dripping water. When pump is good its dry as a bone on the outside.

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