Leaking raw water pump - how serviceable?

[Poey50]

The Johnson F5B-9 raw water pump on my Nanni 3.100HE engine has a steady drip. I thought originally it might be a a leaky cover plate but I've just fitted a Speedseal and it now looks like the leak is coming elsewhere from the pump - although hard to pinpoint since it only leaks with the engine running.

I see there are some service kits around (although my cover plate has six holes and these seem to be four hole ones for a reason I don't understand), but has anyone done this job? Obviously 'how hard?' is a piece of string question, but any advice is welcome.

 

[sailorman]

the lip seal to the shaft is u/s, easy to replace get parts from a factor but make sure you get ss spring in the seal.
How To might be on youtube


http://www.ybw.com/forums/showthread.php?211366-Raw-water-pump-seals

https://www.youtube.com/watch?v=Gcx1rHRXAkI&app=desktop

 

[charles_reed]

The Johnson F5B-9 raw water pump on my Nanni 3.100HE engine has a steady drip. I thought originally it might be a a leaky cover plate but I've just fitted a Speedseal and it now looks like the leak is coming elsewhere from the pump - although hard to pinpoint since it only leaks with the engine running.

I see there are some service kits around (although my cover plate has six holes and these seem to be four hole ones for a reason I don't understand), but has anyone done this job? Obviously 'how hard?' is a piece of string question, but any advice is welcome.

I have a Johnson pump on my 3YM20. I find I get about 500 hours out of an impeller and about 1200 hrs out of bearings and seals. For that reason I have a spare pump (bought from Johnson not Yanmar) and always carry a fully serviced pump - new bearings, seals and impeller.
My last rebuild, including all parts, cost €25 in Chios town.
Whilst it's not difficult to replace bearings and seals, it's a fairly skilled job and I'd advise not trying to do it yourself on the boat as removing and pressing in the new bearing and seal requires a bench.
It is, IMHO, a total waste of time to replace the seal without also replacing the bearing, the additional cost is small change.
For parts, quote the pump type # stamped on the outside of the cover-plate. Order either from ASAP or Johnson Pumps. Don't use non-OEM parts, aftrermarket seals and bearings have a horrible habit of rusting up and wearing out in 10s of hours.
For me the Speedseal is redundant - I've never had a problem changing impellers or ever a leak from the faceplate. Just make sure the O-ring is seated and undamaged.

 

[Poey50]

I have a Johnson pump on my 3YM20. I find I get about 500 hours out of an impeller and about 1200 hrs out of bearings and seals. For that reason I have a spare pump (bought from Johnson not Yanmar) and always carry a fully serviced pump - new bearings, seals and impeller.
My last rebuild, including all parts, cost €25 in Chios town.
Whilst it's not difficult to replace bearings and seals, it's a fairly skilled job and I'd advise not trying to do it yourself on the boat as removing and pressing in the new bearing and seal requires a bench.
It is, IMHO, a total waste of time to replace the seal without also replacing the bearing, the additional cost is small change.
For parts, quote the pump type # stamped on the outside of the cover-plate. Order either from ASAP or Johnson Pumps. Don't use non-OEM parts, aftrermarket seals and bearings have a horrible habit of rusting up and wearing out in 10s of hours.

Thanks for this. Depending on cost, I might go for a new pump straight away and then give myself plenty of time to service the existing one to keep onboard as a spare.

 

[sailorman]

Thanks for this. Depending on cost, I might go for a new pump straight away and then give myself plenty of time to service the existing one to keep onboard as a spare.

seals are a few£s a new pump £200 + possible a lot more