Raw Water Pump Leak

[noelex 77]

I had a small leak from the rear drip hole of the water pump">raw water pump of my 12v generator last time I ran it.
It’s a 15Hp Nanni 2.50HE with a couple of big alternators. 900 hours over 10 years.


Today no leak.
A couple of questions.
Is it safe to run with the small leak. The oil looks fine and it’s a big weep hole so there does not seem much risk for water getting into the engine. Is this correct?
I ran it today and there is no leak at all. Does the pump need a rebuild or is there a chance it was just a bit of debris in the seal?

[TOM]

The pump will have a sling washer which stops water getting into the motor .It is most probably the lip seal that needs replaceing .This is a relativly easy job but does require removeing the pump. I just did ours on our Yanmar.

www.byamee.com

[Tellie]

If only broke things fixed themselves on our boats. Yeah, a leak from a weep hole is a sign of failure. Fix it now while you have the time.

[MarkSF]

Originally Posted by noelex 77

I had a small leak from the rear drip hole of the raw water pump of my 12v generator last time I ran it.
It’s a 15Hp Nanni 2.50HE with a couple of big alternators. 900 hours over 10 years.


Today no leak.
A couple of questions.
Is it safe to run with the small leak. The oil looks fine and it’s a big weep hole so there does not seem much risk for water getting into the engine. Is this correct?
I ran it today and there is no leak at all. Does the pump need a rebuild or is there a chance it was just a bit of debris in the seal?

What I found is that the leaking salt water rapidly makes a right mess of the engine block and the pump body itself. The pump body on mine was one big lump of rust.

If you have designs on just fixing the seal, do it ASAP, before too much corrosion sets in.

On mine I couldn't fix the seal, because the circlip that retains the shaft had corroded solid to the shaft.

[delmarrey]

All of the above + once a seal starts to go then the bearings are next if not caught in time.
Liquid is attracted to heat (Hydrophile), 82º F being the highest saturation. When the bearings are hot they are fine, but when they start to cool the moisture creeps towards them and eventually gets past the bearing shield causing the bearing to pit. A new bearing has lots of grease but after use and getting hot a residual amount is all that's left. It's all down hill from there.

[MikeTurner]

Agree with MarkSF above, on my boat raw water pump seal failure lead to weep hole drip that in turn corroded timing cover, leading to oil leak. When I found the hole beginning to weep it was by no means the first time it had happened, the PO had painted over a fair amount of rust on the timing cover. Had to replace pump, timing cover and associated seals/gaskets.

[MarkSF]

With hindsight, I had been noticing the bilge pad under the engine was wet and stained red by rusty water. I thought it was normal drippage from the propshaft seal but it wasn't, it was the raw water pump.

[terrymccann]

Re Raw Water Pump Leak
Fix it asap and have a pump specialist do, so that its done correctly(I saw the drip 2 months ago, but did nothing)...... . I've now just gone through a very expensive excercise after finding emulsion when checking the oil dipstick on my Yanmar 4LH-HTE it is virtually impossible to use a vacuum pump to draw the emulsified oil out and the previous owner was a complete turkey who blanked off one sump plug and used LOCTITE on the other. I had to add Wynn's gunge cleaner and parafin to thin the oily mess, before I could slowly pump out. Its now cost me 10 litres of Shell Rotella X to flush the sump, a new oil filter, $300 to have the pump rebuilt, plus 4 days of my own labour to first remove the oil cooler, then the raw water pump and its badly located studs to find the problem.

[noelex 77]

Thanks for all the replies and keep them coming

It looks like it can do internal damage as per Terrymccann’ s post. I don’t quite understand why as I understand it the oil seal is separate and if you had a leak in this seal the oil pressure would force oil out of the weep hole.

I think I will probably replace the whole pump as finding someone reliable to rebuild it is not going to easy and I have not been able to find a rebuild kit yet to do the job myself. So corrosion within the pump is less of a concern. The leak has stopped so there is no danger of external corrosion now.


I will start another thread about the correct gasket material

[Tellie]

Keep the old one and rebuild it yourself later when you have access to parts. A complete spare pump on board is golden.

[noelex 77]

Originally Posted by Tellie

Keep the old one and rebuild it yourself later when you have access to parts. A complete spare pump on board is golden.

Thanks Tellie. Good suggestion. Redundancy is always good in a crusing boat. It is probably a bit excessive given that the solar panels provide 100% of the power for 10 months of the year, but I think that is what I will do.

[MarkSF]

Originally Posted by noelex 77

Thanks for all the replies and keep them coming

It looks like it can do internal damage as per Terrymccann’ s post. I don’t quite understand why as I understand it the oil seal is separate and if you had a leak in this seal the oil pressure would force oil out of the weep hole.

I think I will probably replace the whole pump as finding someone reliable to rebuild it is not going to easy and I have not been able to find a rebuild kit yet to do the job myself. So corrosion within the pump is less of a concern. The leak has stopped so there is no danger of external corrosion now.


I will start another thread about the correct gasket material

The pump's oil seal is not exposed to full oil pressure, it's in a splash lubricated region.

[TOM]

Originally Posted by noelex 77

Thanks for all the replies and keep them coming

It looks like it can do internal damage as per Terrymccann’ s post. I don’t quite understand why as I understand it the oil seal is separate and if you had a leak in this seal the oil pressure would force oil out of the weep hole.

I think I will probably replace the whole pump as finding someone reliable to rebuild it is not going to easy and I have not been able to find a rebuild kit yet to do the job myself. So corrosion within the pump is less of a concern. The leak has stopped so there is no danger of external corrosion now.


I will start another thread about the correct gasket material

These things are not difficult to fix . Yours is leaking water so it is the Lip seal ,just take the pump off get a cross section drawing from the pump supplier .Depending on the pump it may have a mechanical lip seal ,a bearing and seal shop will be able to supply you one at half the price Johnson pumps will. These pumps are fairly simple things and it is good to know how they work.
A new bolt on pump is a nice luxury but will be exspensive .With regards to gaskets all you need is gasket paper {to make your own } and a bit of grease.
I was going to send ours to a pump specialist but i"m glad i did'nt as i learnt alot.
Ours was a Johnson pump .Johnson quoted me $75 us for the lip seal plus postage. I got the exact same seal for $24 from a bearing store.
Hope this helps
www.byamee.com

[zeehag]

my raw waterpump leaked like a seive from sd to cedros.. replaced it there with one i had as a spare.
in sd grease was placed and we ran fine until grease left pump and then leaked a bit.... more water got into engine than not, so was ok.
would be a good idea to rebuild the one you have and buy another as a spare.
smooth sailing.

[colemj]

Originally Posted by TOM

These things are not difficult to fix . Yours is leaking water so it is the Lip seal ,just take the pump off get a cross section drawing from the pump supplier .Depending on the pump it may have a mechanical lip seal ,a bearing and seal shop will be able to supply you one at half the price Johnson pumps will. These pumps are fairly simple things and it is good to know how they work.
A new bolt on pump is a nice luxury but will be exspensive .With regards to gaskets all you need is gasket paper {to make your own } and a bit of grease.
I was going to send ours to a pump specialist but i"m glad i did'nt as i learnt alot.
Ours was a Johnson pump .Johnson quoted me $75 us for the lip seal plus postage. I got the exact same seal for $24 from a bearing store.
Hope this helps
www.byamee.com

I just bought lip seals for a Johnson pump from depco.com for $6.23 each.

Mark