PSS shaft seal, leaking.

[SimonA]

I had a PSS seal fitted about two years ago, the boat has been out of the water for the past eight months for some repairs. Now it's back in the shaft seal is leaking water. I have a bilge full after about a week. The marina engineers say it will stop leaking when the boat has been used as the carbon needs to run against the stainless steel, that won't happen for a while as they are refitting my engine. It didn't leak at all before the boat was on hardstanding.

What I want to know is if I'll have this issue every time the boat has been out of the water?

 

[omega2]

Why not fit an automatic bilge pump, that will put your mind at rest until you use the boat again. RULEMATE is a good one.

 

[SimonA]

Why not fit an automatic bilge pump, that will put your mind at rest until you use the boat again. RULEMATE is a good one.

Trouble is I have no power at the moment. Wires are all over the place in my engine bay as the engine has been out. I can't connect the batteries up in case I short anything out.

I suppose I could connect a bilge pump directly to a battery with croc clips for now.

 

[CSFenwick]

Unless the engine re-alignment involved a major change in angles I'd be surprised if that was the problem. There should be enough give in the bellows to make them seal flat together if they did before. Are you sure the carbon face wasn't scratched when she was out, or could there be some debris in there stopping the faces from sealing? A quick flush through (push the bellows back momentarily so water surges through) should clear any debris.

Is there enough pressure on the stainless collar - i.e. is the bellows loaded sufficiently? I seem to remember that the stainless steel collar should be positioned so as to compress the bellows by about an inch (but look on the PSS website for confirmation).

My PSS seal has been great. No leaks in 4 years and no problems when the boat goes back in the water. Are you sure it's coming in from there?

 

[Robin]

It is usual to have to 'burp' air out of the system with these face seals after a re-launch unless you have one which is fitted with a water injection from the engine. We have a PSS on a yacht and have a hose from the water inlet connection to above the waterline and this allows the air to escape as the boat is launched. In your case with a mobo I would expect the seal to need water injection and with the engine removed maybe this has been blocked off? Smaller engines and slower speeds mean the water injection isn't needed but the connection can be used as an automatic bleed like ours.

 

[Tranona]

If it is leaking between the faces it can either be damaged faces - unlikely, debris between the two faces, possible, or incorrect pressure from the bellows. One of the downsides of these seals is that they seal under pressure from the bellows and the instructions are clear about that. It is not easy to do with the engine disconnected as the shaft is the free to move back and forth. If the yard has put it back in the water without the engine connected to the shaft it is their problem and they should haul the boat immediately at their cost.

 

[omega2]

Trouble is I have no power at the moment. Wires are all over the place in my engine bay as the engine has been out. I can't connect the batteries up in case I short anything out.

I suppose I could connect a bilge pump directly to a battery with croc clips for now.

the rulemate will look after itself, just croc clip to a battery for now.

 

[sailorman]

http://www.shaftseal.com/about/installation_instructions

 

[aquatom]

I agree with Tranona. If the engine is out then the shaft will be free to move forward meaning less preshure on the seal. I would have thought the person who removed the engine would be responsible for sorting this out. You may be able to stop it by pulling the shaft back with a rope attached to the coupling.

 

[Robin]

I agree with Tranona. If the engine is out then the shaft will be free to move forward meaning less preshure on the seal. I would have thought the person who removed the engine would be responsible for sorting this out. You may be able to stop it by pulling the shaft back with a rope attached to the coupling.

Yes, on reflection I too think this is the most likely reason.

 

[SimonA]

It is usual to have to 'burp' air out of the system with these face seals after a re-launch unless you have one which is fitted with a water injection from the engine. We have a PSS on a yacht and have a hose from the water inlet connection to above the waterline and this allows the air to escape as the boat is launched. In your case with a mobo I would expect the seal to need water injection and with the engine removed maybe this has been blocked off? Smaller engines and slower speeds mean the water injection isn't needed but the connection can be used as an automatic bleed like ours.

I only have a displacement boat, so the PSS has the vent hose which exits above the water level, it isn't connected to the engine.

I can only go on what the engineers are telling me as I haven't inspected it. I suspect it might be some dirt or something between the faces from what I have read about these. They told me they had to burp it when launching, and now it isn't sealing.

 

[Tranona]

They don't need burping. That is for Volvo seals. Burping is to expell air and if water is comming out of the faces there is clearly not a problem with air!

Pretty sure the problem will be incorrect bellows pressure. If the shaft is not connected to the engine then it can move forward so relaxing the bellows. Then water pressure forces water between the faces.

I would be concerned about putting a boat in the water with this kind of seal if the shaft is not connected.

It is different with conventional stuffing boxes and lip seals such as the Volvo which make the seal around the shaft so broadly speaking they will not leak provided the shaft goes through the seal. I am not sure your "engineers" understand the difference.

 

[bendyone]

They don't need burping.

I had one on the last boat, they do need burping. It is important to do it.

 

[Bilgediver]

I had a PSS seal fitted about two years ago, the boat has been out of the water for the past eight months for some repairs. Now it's back in the shaft seal is leaking water. I have a bilge full after about a week. The marina engineers say it will stop leaking when the boat has been used as the carbon needs to run against the stainless steel, that won't happen for a while as they are refitting my engine. It didn't leak at all before the boat was on hardstanding.

What I want to know is if I'll have this issue every time the boat has been out of the water?

If the engine was removed and serviced and the coupling not fitted exactly as it had before then the shaft could be slightly out of position You may find that if the shaft is disconnected then the leakage can be stopped by pushing the shaft aft however the seal location on the shaft may have to be readjusted to suite the set up after the engine installation is completed. Your service company will of course be aware of this.