I've been trying to track down some odd shaft noises and have been searching the archives and reading your PYI web site. Discovered that the PSS dripless seal has to be "burped" after haulout. I never knew this! I hauled the boat out last month, and have about three hours on the engine since...what kind of damage might I have done by not burping the seal?
Didn't burp dripless seal...
- Thread starter Dean Strong
- Start date
- Status
forgot to "burp"
I would guess ,if there is no problem now (like a leak) that you did not damage the pss shaft seal. the reason for burping it is to have water for cooling and lubrication. Check your bellows to make sure that is is OK and keep a eye on it the next few times you use it but I would not be overly concerned unless there is a problem now.
I would guess ,if there is no problem now (like a leak) that you did not damage the pss shaft seal. the reason for burping it is to have water for cooling and lubrication. Check your bellows to make sure that is is OK and keep a eye on it the next few times you use it but I would not be overly concerned unless there is a problem now.
Pete is right
The danger is heating the bellows and damageing the material. When you do burp, protect yourself with a towel. The water will spray with incredible force. Failure of a bellows will sink a boat in a hurry. It is an eye opener.
The danger is heating the bellows and damageing the material. When you do burp, protect yourself with a towel. The water will spray with incredible force. Failure of a bellows will sink a boat in a hurry. It is an eye opener.
No Burp
Dean, I have used PSS since 1996. Though I always burp it I also use white bottom paint. This goes green above the water line due to the copper oxidising in contact with air. Below WL it stays white. Whenever I haul my boat the paint up inside the log tunnel is always green indicating an air pocket must form so depriving the bearing of its water lubrication and cooling. Had no overheating or leakage problems and now have over 1000 hrs on the engine. Your 3 hrs would hardly seem to matter, unless the seal is over compressed and the engine run flat out. Just my experience. Your odd noises may be due to the shaft not running in the centre of the log tube and banging against it under certain engine speeds. If it does this the noise can be worryingly loud. If your noises are not loud then this might not be the cause. Regards for Christmas.
Dean, I have used PSS since 1996. Though I always burp it I also use white bottom paint. This goes green above the water line due to the copper oxidising in contact with air. Below WL it stays white. Whenever I haul my boat the paint up inside the log tunnel is always green indicating an air pocket must form so depriving the bearing of its water lubrication and cooling. Had no overheating or leakage problems and now have over 1000 hrs on the engine. Your 3 hrs would hardly seem to matter, unless the seal is over compressed and the engine run flat out. Just my experience. Your odd noises may be due to the shaft not running in the centre of the log tube and banging against it under certain engine speeds. If it does this the noise can be worryingly loud. If your noises are not loud then this might not be the cause. Regards for Christmas.
Dripless seal woes and risks
Had similar problems as described by Dean with a relatively new PYI system (re-installed in Townsville, Australia 5 months earlier) while motoring into the big lagoon near Vuda Point marina (Fiji) to haul "Rivendel II" out for the cyclone season. Thought at first that it was the Hurth transmission till I noticed that the PYI bellows and seal were very, very hot!!! When I tried to burp the seal, hot steam came out!! Thus we motored the last few hours to the marina while pouring cold water over the PYI seal flange and bellows from a teakettle. I believe we came very, very close to disaster then...... Encrusted salt from a small leak (caused by light pressure on the bellows from the floor board!) had apparetnly roughened the surface of the dripless seal enough to cause excessive friction and heating, even at the low engine rpms we typically motor at (max. 2000 rpm). Since the rubber bellows appeared to have lost some of its elasticity we not only modified the floor board but also replaced the entire PYI assembly with the water-cooled PYI model (meant for high rpm power boats). Haven't had any trouble since. Nonetheless, I do have the same ambiguous feelings about the possibility of catastrophic failure as articulated by Jim. Although we have reinforced our Hunter's flimsy fiberglass shaft pipe and frequently inspect the PYI bellows I feel we should have stayed with the old stuffing box (plus new teflon packing, of course). Why risk anything for a few drops of seawater? Our bilge is never totally dry anyhow with all the tropical rains, seawater over the bow, refrigerator defrosting, etc, some of which inevitably finds its way into the bilge. Therefore, I plan to change back to the old stuffing box next time we replace the cutless bearing!! Flying Dutchman
Had similar problems as described by Dean with a relatively new PYI system (re-installed in Townsville, Australia 5 months earlier) while motoring into the big lagoon near Vuda Point marina (Fiji) to haul "Rivendel II" out for the cyclone season. Thought at first that it was the Hurth transmission till I noticed that the PYI bellows and seal were very, very hot!!! When I tried to burp the seal, hot steam came out!! Thus we motored the last few hours to the marina while pouring cold water over the PYI seal flange and bellows from a teakettle. I believe we came very, very close to disaster then...... Encrusted salt from a small leak (caused by light pressure on the bellows from the floor board!) had apparetnly roughened the surface of the dripless seal enough to cause excessive friction and heating, even at the low engine rpms we typically motor at (max. 2000 rpm). Since the rubber bellows appeared to have lost some of its elasticity we not only modified the floor board but also replaced the entire PYI assembly with the water-cooled PYI model (meant for high rpm power boats). Haven't had any trouble since. Nonetheless, I do have the same ambiguous feelings about the possibility of catastrophic failure as articulated by Jim. Although we have reinforced our Hunter's flimsy fiberglass shaft pipe and frequently inspect the PYI bellows I feel we should have stayed with the old stuffing box (plus new teflon packing, of course). Why risk anything for a few drops of seawater? Our bilge is never totally dry anyhow with all the tropical rains, seawater over the bow, refrigerator defrosting, etc, some of which inevitably finds its way into the bilge. Therefore, I plan to change back to the old stuffing box next time we replace the cutless bearing!! Flying Dutchman
To little time to damage
Hello Dean, Thank you for your note describing the forgot burping procedure. The damage that can occur, after many hours of dry use, is a glossing of the contact faces. If that occurred you would simply flat sand the surface with a 600 wet/dry sand paper to remove the glossed material. The Carbon has a far amount of self lubrication and its not until the polymer that holds the carbon together begins to gloss does the seal face suffer a problem. A few hours of run time should not have created any adverse problems for you. I would like to say that one note listed in the responses stated near failure with his carbon seal. I think it needs to be pointed out that even though the seal was installed incorrectly and functioned out of its designed range it still functions and did not fail. What was described in that response is not an uncommon occurrence when the packing of a traditional stuffing box is to tight around the shaft limiting and eliminating the needed water for lubrication. The same thing happens to any seal that is starved of lubrication. Hope this helps. Kevin
Hello Dean, Thank you for your note describing the forgot burping procedure. The damage that can occur, after many hours of dry use, is a glossing of the contact faces. If that occurred you would simply flat sand the surface with a 600 wet/dry sand paper to remove the glossed material. The Carbon has a far amount of self lubrication and its not until the polymer that holds the carbon together begins to gloss does the seal face suffer a problem. A few hours of run time should not have created any adverse problems for you. I would like to say that one note listed in the responses stated near failure with his carbon seal. I think it needs to be pointed out that even though the seal was installed incorrectly and functioned out of its designed range it still functions and did not fail. What was described in that response is not an uncommon occurrence when the packing of a traditional stuffing box is to tight around the shaft limiting and eliminating the needed water for lubrication. The same thing happens to any seal that is starved of lubrication. Hope this helps. Kevin
Didn,t burb
Bought this boat a year ago.It came with a dripless already installed. I have had the boat out of the watersince but did not know you had to burb the dripless and dont even know how. I would guess there is over 150 hrs on it since. Can you tell me how to burb it as there are no instructions on the boat covering this. Thanks Alan Jepson
Bought this boat a year ago.It came with a dripless already installed. I have had the boat out of the watersince but did not know you had to burb the dripless and dont even know how. I would guess there is over 150 hrs on it since. Can you tell me how to burb it as there are no instructions on the boat covering this. Thanks Alan Jepson
To Quote Someone Else, Alan...
"To 'burp' the seal simply grasp the rubber bellows at the end closest to your engine--the side that rests against a stainless steel doughnut around the shaft--and pull it back towards the stern. You only have do this for a second or two until water comes out". This is the process I have always followed. If you had a yard launch, they may have done it for you. Rick D.
"To 'burp' the seal simply grasp the rubber bellows at the end closest to your engine--the side that rests against a stainless steel doughnut around the shaft--and pull it back towards the stern. You only have do this for a second or two until water comes out". This is the process I have always followed. If you had a yard launch, they may have done it for you. Rick D.
- Status