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Post by sitara on Sept 21, 2019 6:27:04 GMT
The raw water pump on my Yanmar 3YM30 engine started leaking from the weep hole after about five years of use. Being intimidated by the thought of lip seals and bearings I took the pump to the experts. Problem solved for about a year but then the pump started leaking again. This time I was going to do it myself. Googling found numerous posts and you tube videos on how to do it.  The pump is a Johnson F4B 903. Drawings and parts list are provided in the Johnson catalogue “Flexible impeller puts for marine use” (I found it at www.glasgowengineering.com.au/uploads/general/Johnson-Pump-Catalogue.pdf with the F4B 903 being described on page 40). The key components needed are two ball bearings of sizes ISO 6201 2RS and ISO6001 2RS. These have dimensions of 12 x 32 x 10 mm and 12 x 28 x 8 mm respectively (shaft diameter x outside diameter x thickness). I purchased stainless steel variants given the pump environment. Also need is the lip seal Yanmar part number X02233010 with dimensions 12 x 24 x 7 mm in nitrile rubber. Here I purchased a generic lip seal (the price was right).  www.23hq.com/Sitara/photo/60247171/originalMy procedure 1. Remove the impeller. 2. Remove the pulley. Use a metal slug in a vice slotted into the impeller groove on the shaft to stop it turning. 3. Remove pump from support. This had corroded and needed cleaning and painting with zinc rich paint. 4. Remove the hexagonal nut that retains the bearing on the shaft. This was hidden by the pulley and is reverse threaded so clockwise to loosen. 5. Remove the retaining ring that locks the bearings and shaft in the brass housing. Now the shaft can be pushed out. I used the above metal slug to apply pressure to the shaft and a hardwood block with a hole that would just take the bearing and still support the brass housing. All squeezed together in a bench vice. 6. Now you have access to the lip seal and the o-ring beneath it and will be able to remove them. If your bearings are in good condition reassemble and replace the lip seal. I pushed the lip seal in from the impeller side taking care that there were no sharp edges to damage the seal. In my case one of the bearings was rough to turn so I replaced both. Use google to find instructions on how to remove and replace bearings. I used a propeller puller to remove the bearings, not good if you are reusing the bearings as it pulls on the outer ring. To push the new bearings onto the shaft I used brass plumbing fittings that pushed neatly on the inner ring, all in a bench vice with a hardwood block to protect the shaft. The pump has been running now for (only) several hours with no leaks. Has my repair worked? I guess I will know by the end of next season. Any comments on this process are most welcome as I am not a mechanic.
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Post by zaphod on Sept 21, 2019 18:06:40 GMT
It sounds like you did everything correctly. One tip I will offer: when pressing the new bearings onto the shaft, if you put the shaft in the freezer for a couple of hours it will shrink slightly, and the bearings will probably just slip right on with very little force.
Failing that, using a brass pipe fitting to put even force on the inner race was a good call.
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Post by sitara on Sept 21, 2019 21:14:12 GMT
Thanks zaphod, The freezer tip is a great idea, there was a lot of force needed to push the bearings onto the shaft.
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Post by sailbleu on Sept 27, 2019 9:27:43 GMT
After a leak it's a rule to also replace the bearings ( and why not the impeller too) , the salt water will ruin everything in no time .
As for the leak itself , if or when the seal is leaking again after 1 year of use it could indicate a problem with the shaft
The seal lip is in a fixed position on the shaft , and although being rubber it will cause a groove in the shaft after some time . The diameter will be less and the seal lip (even a new one) will not ensure a waterproof situation .
Then it's either finding a smaller seal , replacing the shaft ( outrageously expensive for what is) or go for a speedy sleeve .
If you visit the H&T section and look for " raw water pump repair " you will find the procedure .
Regards
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Post by quixotic on Jul 16, 2020 12:58:16 GMT
The raw water pump on my Yanmar 3YM30 engine started leaking from the weep hole after about five years of use. Being intimidated by the thought of lip seals and bearings I took the pump to the experts. Problem solved for about a year but then the pump started leaking again. This time I was going to do it myself. Googling found numerous posts and you tube videos on how to do it. The pump is a Johnson F4B 903. Drawings and parts list are provided in the Johnson catalogue “Flexible impeller puts for marine use” (I found it at www.glasgowengineering.com.au/uploads/general/Johnson-Pump-Catalogue.pdf with the F4B 903 being described on page 40). The key components needed are two ball bearings of sizes ISO 6201 2RS and ISO6001 2RS. These have dimensions of 12 x 32 x 10 mm and 12 x 28 x 8 mm respectively (shaft diameter x outside diameter x thickness). I purchased stainless steel variants given the pump environment. Also need is the lip seal Yanmar part number X02233010 with dimensions 12 x 24 x 7 mm in nitrile rubber. Here I purchased a generic lip seal (the price was right). www.23hq.com/Sitara/photo/60247171/originalMy procedure 1. Remove the impeller. 2. Remove the pulley. Use a metal slug in a vice slotted into the impeller groove on the shaft to stop it turning. 3. Remove pump from support. This had corroded and needed cleaning and painting with zinc rich paint. 4. Remove the hexagonal nut that retains the bearing on the shaft. This was hidden by the pulley and is reverse threaded so clockwise to loosen. 5. Remove the retaining ring that locks the bearings and shaft in the brass housing. Now the shaft can be pushed out. I used the above metal slug to apply pressure to the shaft and a hardwood block with a hole that would just take the bearing and still support the brass housing. All squeezed together in a bench vice. 6. Now you have access to the lip seal and the o-ring beneath it and will be able to remove them. If your bearings are in good condition reassemble and replace the lip seal. I pushed the lip seal in from the impeller side taking care that there were no sharp edges to damage the seal. In my case one of the bearings was rough to turn so I replaced both. Use google to find instructions on how to remove and replace bearings. I used a propeller puller to remove the bearings, not good if you are reusing the bearings as it pulls on the outer ring. To push the new bearings onto the shaft I used brass plumbing fittings that pushed neatly on the inner ring, all in a bench vice with a hardwood block to protect the shaft. The pump has been running now for (only) several hours with no leaks. Has my repair worked? I guess I will know by the end of next season. Any comments on this process are most welcome as I am not a mechanic.
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Post by quixotic on Jul 16, 2020 13:13:53 GMT
My 5 year old Yanmar 3GM30 also developed a leak from the raw water pump. Rather than replace the worn shaft, I purchased an SKF Hardened stainless speedi sleeve for shafts 0.469 - 0.475. It comes with a tube/drift to drive the sleeve onto the shaft and the new 12 x 24 x 4.5mm nitrate seal accommodates the slightly larger diameter. Total cost £30 from Simply bearings.
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Post by no3l on Jul 18, 2020 15:19:25 GMT
Hi
I am in the middle of the same process. I have serviced the pump, replacing seals, bearings and impeller but now I cannot get the sea water to flow. I have tried everything I can think of, including following Vaskos post from a while ago ie.
1. close the inlet tap
2. open the filter
3. clean the filter etc.
4. fill the filter with water to the top ( if not you will get a air blockage)
5. close the lid lightly
6. open the inlet tap
Water is flowing freely through the inlet and from the filter to the pump.
During the service I also replaced the elbow and hose tail at the raw water intake but I don't think this will have any effect.
Thanks in advance.
Noel
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Post by no3l on Jul 23, 2020 22:05:10 GMT
Hi All,
The solution was that the pump was mounted incorrectly. When refitting It is possible to fit the pump turned through 180 degrees in which case it will not work.
I understood that the pump was bidirectional but it seems that this is not the case.
Regards
Noel
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Post by sitara on Jul 23, 2020 22:17:03 GMT
Glad you resolved it Noel, that was one problem I had not thought of. Cheers Rob
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Post by blade on Nov 20, 2020 14:28:44 GMT
The raw water pump on my Yanmar 3YM30 engine started leaking from the weep hole after about five years of use. Being intimidated by the thought of lip seals and bearings I took the pump to the experts. Problem solved for about a year but then the pump started leaking again. This time I was going to do it myself. Googling found numerous posts and you tube videos on how to do it. The pump is a Johnson F4B 903. Drawings and parts list are provided in the Johnson catalogue “Flexible impeller puts for marine use” (I found it at www.glasgowengineering.com.au/uploads/general/Johnson-Pump-Catalogue.pdf with the F4B 903 being described on page 40). The key components needed are two ball bearings of sizes ISO 6201 2RS and ISO6001 2RS. These have dimensions of 12 x 32 x 10 mm and 12 x 28 x 8 mm respectively (shaft diameter x outside diameter x thickness). I purchased stainless steel variants given the pump environment. Also need is the lip seal Yanmar part number X02233010 with dimensions 12 x 24 x 7 mm in nitrile rubber. Here I purchased a generic lip seal (the price was right). www.23hq.com/Sitara/photo/60247171/originalMy procedure 1. Remove the impeller. 2. Remove the pulley. Use a metal slug in a vice slotted into the impeller groove on the shaft to stop it turning. 3. Remove pump from support. This had corroded and needed cleaning and painting with zinc rich paint. 4. Remove the hexagonal nut that retains the bearing on the shaft. This was hidden by the pulley and is reverse threaded so clockwise to loosen. 5. Remove the retaining ring that locks the bearings and shaft in the brass housing. Now the shaft can be pushed out. I used the above metal slug to apply pressure to the shaft and a hardwood block with a hole that would just take the bearing and still support the brass housing. All squeezed together in a bench vice. 6. Now you have access to the lip seal and the o-ring beneath it and will be able to remove them. If your bearings are in good condition reassemble and replace the lip seal. I pushed the lip seal in from the impeller side taking care that there were no sharp edges to damage the seal. In my case one of the bearings was rough to turn so I replaced both. Use google to find instructions on how to remove and replace bearings. I used a propeller puller to remove the bearings, not good if you are reusing the bearings as it pulls on the outer ring. To push the new bearings onto the shaft I used brass plumbing fittings that pushed neatly on the inner ring, all in a bench vice with a hardwood block to protect the shaft. The pump has been running now for (only) several hours with no leaks. Has my repair worked? I guess I will know by the end of next season. Any comments on this process are most welcome as I am not a mechanic.
Hi Sitara, I am just in the process of overhauling the same raw water pump. I have removed it, taken off the pulley, retaining clip and am at the stage of trying to remove the shaft and bearings. Can you recall how much effort was required when using the vice to remove it, did it just come out by gradually winding up the vice or did it take some other persuasion, hopefully you can recall as it from last year. Thanks Barry McCrae |
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Post by sitara on Nov 20, 2020 20:26:11 GMT
Hi Barry, The shaft and bearings came out fairly easily as I tightened the vice. The bearings were much more tightly fitted to the shaft. Good luck with this, my water pump is still not leaking so I am pretty pleased with the result. It seems with the previous repair, done by a professional pump business, that the lip seal was inserted with the spring on the water side, this corroded away quickly and leaked again. Good luck, let us know how it works out.
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Post by blade on Nov 24, 2020 15:43:55 GMT
Hi Barry, The shaft and bearings came out fairly easily as I tightened the vice. The bearings were much more tightly fitted to the shaft. Good luck with this, my water pump is still not leaking so I am pretty pleased with the result. It seems with the previous repair, done by a professional pump business, that the lip seal was inserted with the spring on the water side, this corroded away quickly and leaked again. Good luck, let us know how it works out.
Hi Sitara, Thanks for the info above. I think my bearings were possibly a little more corroded, it took quite a bit of force to move them as the vice was tightened. The larger (outer) bearing came out but unfortunately the inner bearing parted, the inner race came out but left the outer race inside the pump housing - a big scratch of head. Fabricated a tool to press on the polycarbonate disc (with slots cut into it to protect the small pips on the disc), used the vice again to gently push this out, luckily the outer race moved and the disc came out undamaged. The shaft was put in the freezer this morning and I have just reassembled all the new parts and seals. Will put back into the boat tomorrow morning - keeping fingers crossed for a successful result. |
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Post by sitara on Nov 24, 2020 21:35:26 GMT
Glad it worked Barry, I did not touch the polycarbonate disc. Was their much corrosion under the ball race? Hope it all goes well when you test it. Rob
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Post by blade on Nov 25, 2020 22:23:08 GMT
Glad it worked Barry, I did not touch the polycarbonate disc. Was their much corrosion under the ball race? Hope it all goes well when you test it. Rob
Hi Sitara, not much corrosion under the ball race, very minimal cleaning up required. Pump now re-installed, a little difficult getting the new pump drive belt back on but all tested and working perfectly again. Thanks again for the detailed explanation and link to pdf drawing of the pump. |
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