Before starting your installation, carefully read the following warnings and instructions. Failure to properly follow the warnings and instructions could lead to personal injury or even death or physical, environmental, or property damage.
The PSS (Packless Sealing System) Shaft Seal ("PSS") you are preparing to install is a through-hull fitting that protects against water from entering the boat where the shaft enters the hull when properly installed and maintained. Make sure that you or your designated installer is a qualified professional, knowledgeable, and skilled to install the PSS correctly and that you have all the required tools and additional equipment on hand before beginning installation.
The PSS Shaft Seal is a mechanical face seal that is created between the flat surfaces of the rotating stainless steel rotor and the stationary carbon flange. The stationary carbon flange is attached to the vessel's stern tube with hose clamps and the carbon flange is attached to the front side of the bellows with hose clamps. The stainless steel rotor is fits on the shaft in front of the carbon flange. The stainless steel rotor is used to compress the bellows before the collar is secured to the shaft with set screws. This compression (pre-load) maintains contact between the faces and allows the PSS to compensate for the thrust from the propeller. The carbon flange is bored larger than the shaft diameter allowing it to “float” around the shaft and thus compensate for most misalignment and vibration problems. The stainless steel collar is sealed to the shaft by two o-rings that are recessed into the bore of the collar. These o-rings rotate with the shaft and stainless steel rotor and do not experience wear during operation.
In all cases, the boat must be out of the water to perform this installation.
|Shaft Diameter||Compression Amount|
|3/4" to 1-3/8"
(20mm to 35mm)
|1-1/2" to 3-3/4"
(38mm to 95mm)
|Shaft Diameter||Compression Amount|
|3/4" to 2-1/2"
(20mm to 65mm)
|2-3/4" to 3-3/4"
(70mm to 95mm)
* The suggested 1" of compression is an average load. Up to 1-1/2" of compression can be applied, if necessary.
|Shaft Diameter||Compression Amount|
|4" to 6"
(100mm to 150mm)
Low speed boats: (Under 12 knots of boat speed under power and no bearing in the shaft log).
Using a 3/8" (8mm or 9mm) ID "underwater rated" hose (not provided with the PSS), connect the hose to the hose barb fitting installed on the carbon and secure the hose with two (2) hose clamps. Run the hose to a point in the boat at least two (2) feet above the waterline, making sure that the hose does not apply any load on the carbon part of the seal. Keep the hose as close as possible to the vessel's centerline, so the top of the vent hose is never below the waterline, even if the boat heels. Secure the hose in place with the necessary fittings that ensure it will not pull free and drop. This hose is now a venting hose that will help ensure that no air is trapped in the seal.
WARNING: Do not run a loop at the top end of the vent hose as it could start a siphon action in some extreme conditions. Make sure the vent hose is properly secured from falling below the waterline. If the vent hose were to fall below the waterline, water would come into the boat. Do not plug or block the end of the vent hose, as this would prevent the line from venting.
High-speed boats: (Over 12 knots of boat speed under power).
Note: Twin engine boats that can exceed 12 knots on a single engine must run a crossover line between seals to ensure both seals maintain water flow while running on only one engine.
For high-speed vessels, it is required that a water supply be plumbed to the PSS for cooling and lubricating the seal faces (i.e., at over approximately 12 knots of speed, a vacuum is created in the stern tube, and water is drawn away from the PSS resulting in a loss of cooling water that may cause the carbon to overheat). There are multiple sources of water for the supply. The following are a few non-exhaustive examples. These are examples only, and they may or may not apply to your particular boat.
If you hear a high-pitched squeal from the PSS shaft seal during operation, the seal may not be getting water. Review and correct plumbing to the seal.
CAUTION: If the seal has run dry, use caution! The faces (stainless steel rotor and carbon) may be very hot.
The dimensions provided in the "bellows compression chart" are average figures and are provided as a guide. The EXACT compression amounts required can vary due to different types of engine mounts and water pressure being fed to the seal. If you experience any spray or mist following the break-in period, make sure that the bellows have been compressed properly. If so, add 1/4" of compression to the seal, and soon the mist should disappear. Keep adjusting until the spray or mist stops.
Suppose the PSS seal drips while at rest, then it is likely that foreign material is on the face of the seal between the stainless steel rotor and the carbon flange. To clean this foreign material from the seal, insert a clean rag carefully between the two faces (Note: some water will come into the boat at this time if the boat is in the water) and work the rag around the seal. As you do this, the incoming water will flush the impurities. Remove the rag from the seal, and the leak should stop.
On average, the PSS requires approximately one (1) hour of break-in time, which allows the carbon flange to polish the mating face of the stainless steel rotor. During the break-in period, you will experience a very fine mist, sometimes associated with black dust coming from the PSS. Under normal conditions, this will stop after an average of one (1) hour running time.
Grant of Limited Warranty. The PSS (Packless Sealing System) Shaft Seal ("PSS")is warranted by PYI, Inc. ("PYI")to the original purchaser only to be free from defects in material and workmanship under normal use and maintenance for a period of three (3) years from the date of first use or shipment, whichever comes first. During the warranty period, all original parts subject to this limited warranty and determined by PYI to be defective in materials or workmanship, will either be repaired or replaced by PYI or its authorized agent, at its sole option, free of charge, except for shipping and handling charges and dealer labor charges (if applicable), which charges are not covered by this limited warranty. The warranty on any part repaired or replaced under this limited warranty expires at the end of the original warranty period.
Limitations of Limited Warranty. This limited warranty does not cover and does not apply to any PSS: (i) altered in any way inconsistent with the shaft seal design as provided, (ii) improperly installed and/or maintained, (iii) incompatible with any portion or component of any boat or application that is not supplied by PYI, regardless of the cause of the failure or incompatibility of such portion or component, (iv) used for purposes other than those for which it was designed, and/or (v) subjected to misuse, neglect or accidents. In order to obtain warranty service, the PSS, together with the bill of sale or other dated proof-of-purchase document identifying the shaft seal model number, must be presented to an authorized PSS dealer during the warranty period. For assistance in locating an authorized PSS dealer, please contact PYI at:PYI, Inc.
Except for the limited warranty expressly provided above, to the maximum extent permitted by applicable law, PYI and its suppliers make no warranties, express or implied, and disclaim all warranties, duties and conditions, whether express, implied or statutory, with respect to the PSS, including, without limitation, any implied warranties of merchantability, against latent defects, fitness for a particular purpose, or correspondence to description.
Limitation of Remedies. In the event of a breach of the limited warranty set forth above, PYI or its authorized agent will only be obligated at PYI’s sole option to either repair or replace the failed PSS. If after written notice to PYI of each defect, malfunction or other failure and a reasonable number of attempts to correct the defect, malfunction or other failure and the remedy fails of its essential purpose, PYI shall refund the purchase price paid to PYI in exchange for the return of the sold good(s). Said refund shall be the maximum liability of PYI. THE FOREGOING REMEDY IS THE SOLE AND EXCLUSIVE REMEDY OF THE BUYER AGAINST PYI REGARDLESS OF THEORY, WHETHER ARISING IN CONTRACT, BREACH OF ANY WARRANTY, TORT, INCLUDING STRICT LIABILITY OR NEGLIGENCE, OR OTHERWISE.
Limitation of Liability. To the maximum extent permitted by applicable law, PYI and its suppliers expressly disclaim and exclude any liability for any incidental, special, indirect or consequential damages resulting from any reason whatsoever. This exclusion applies to all legal theories under which damages may be sought.
Note: This limited warranty gives you specific legal rights and you may also have other rights which may vary from state to state.
Copyright © PYI, Inc. All rights are reserved. No part of this document may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language or computer language, in any form or by any means, without the prior written permission of PYI, Inc.
PYI, Inc. makes no representations or warranties, express or implied, with respect to this document or the contents herein and specifically disclaims any implied warranties of merchantability or fitness for any particular purpose. In addition, PYI, Inc. reserves the right to revise this document and to make changes from time to time in the content hereof.