Shaft Seals

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AlanH
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Shaft Seals

Post by AlanH »

We have had our boat for just about three years and for the first two had problems with the starboard side Tides Marine shaft seal leaking. We had both seals them replaced at Stuart Yacht. Gregg said they had replaced them less than three years earlier for the prior owner. Stuart did not feel we had a shaft problem but we did have the props reconditioned due to RPM issues. We do have the intermediate shaft bearings. The new one leaked again as well. Eventually we had that replaced again. Still leaked.

We tried a new mechanic in St. Augustine and he said we were the third or fourth PDQ that he worked on with shaft seal problems. He convinced me to give PYI PSS shaft seals a try. He said the PSS PYI rep was so convinced that their high vibration seals would work that they were donating them. They asked that if I was happy with them to spread the word. They initially leaked but they are adjustable and after being adjusted have been fine. They can be adjusted with the boat in the water and it can be done by the boat owner.

I decided to wait awhile before writing about this on the forum as I wanted to be sure they lasted. It has been 10 months and the bilges are completely dry. I am very happy with them and would not hesitate to recommend using them.

Alan
Alan Hendry
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2006 34' Hull #81
75hp engines
duetto
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Re: Shaft Seals

Post by duetto »

hi alan,

glad to hear your success. we too had problems with seals, first tides and then pss. we had extra cutlass bearing and things have been good since. i do think pss face seal is more tolerant of vibration than tides lip seal.
john & diane cummings
duetto mv34 #23
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AMCarter3
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Re: Shaft Seals

Post by AMCarter3 »

Alan,

We installed new cutlass bearings and changed to PYI PSS Type A shaft seals a year ago when we had our running gear (shaft & props) removed and repaired. We did have a small leak at one of the seals. As you know, the tightness of the contact between the stainless-steel rotor and the stationary carbon flange can be adjusted to the point where it does not leak. But, even after adjusting the tightness, that seal still leaked a bit. We had that shaft seal removed, examined and replaced under the PYI warranty. Turns out the leak came from a tiny hairline crack in the metal nipple used to attach the raw water hose to the shaft seal. It has essentially not leaked since then.

I learned that it is fairly common with PSS seals to see a tiny amount of water mist coming off the seal when the engines are running hard. I also learned that when our boat is in very turbid water with a lot of fine grit (e.g., from river runoff in the winters), that grit can get in between the rotor and carbon flange and cause a tiny amount of water leakage... neither is enough to worry about.
Mac Carter
2006 34' PDQ PowerCat "All Heart"; MV 98; twin 100 HP Yanmars
Home Port: Bellingham WA 98229
MikeH
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Re: Shaft Seals

Post by MikeH »

At the risk of starting a firestorm on PSS vs. Tides ...

Tides has updated their design - the photo shows the new design next to the old one. I also got the Carrier to enable an in-place replacement of the shaft seal.

I'm doing these in combination with new cutlass bearings, new mid-bearings, and engine alignment, so we'll see how they do !
Attachments
20220127_124053.jpg
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Mike Hendry
M/V Easy Riders, Gulfport FL
2003 PDQ MV 34
The Legendary Hull #29
75 HP, 3 Blade
Nick
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Re: Shaft Seals

Post by Nick »

We are running Tides seals with the cooling water coming off the engine cooling system via a t-joint spliced into cooling line at front of motor. That means I have 8 hose clamps on four connections. There are no problems with the set up, but I can as easily access water for the tides seals through an outlet at the bottom of the exhaust cooler thereby going from 8 hose clamps to 4 and tidying up the top of the motor. Is there any reason not to make the change…..beyond “let sleeping dogs lie”?
Nick & Barb
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James Power
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Re: Shaft Seals

Post by James Power »

Hey Nick,

The T fitting setup will usually fit a single clamp, with the second just cutting into unsupported hose. Good idea to replace any damaged hose if found and eliminate some extra clamps.

James
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Re: Shaft Seals

Post by Nick »

I agree I could tidy up the number of hose clamps, but am wondering about benefits (or downside) to removing the t-connection entirely and running the feed from bottom of inter cooler. Benefits I see are “cleaning up” top of engine while eliminating any risk of a leak dripping seawater onto motor offset by making access to feed somewhat more difficult by putting at bottom of intercooler. Is there a fundamental safety/operating benefit to feed coming from the t connection on top of motor?

BTW,I’m not suggesting a special project to make the change, but I have the intercooler off right now and it would be really easy to do.
Nick & Barb
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Re: Shaft Seals

Post by duetto »

nick,

do you have a t on each engine? maybe i'm wrong but i thought one of the purposes (maybe only) of the t is to allow cooling to both seals if you're running just one engine.
john & diane cummings
duetto mv34 #23
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