You have a Tides shaft seal. This has been identified by members in this thread. The Tide design is a lip seal that can be replaced while the boat is in the water. Tide seals don't leak. If they start to leak with a steady drip or even a slight drip it is time to replace the lip seal. There is normally a spare seal stored in the black "donut" mounted to the shaft. The one draw back to a lip seal is it can wear a grove in the shaft surface. A grove in the shaft can also be a cause for a leak at the seal area. If there is a grove cut in the shaft you can relocate the area that the seal rides on the shaft by loosening the hose clamps and sliding the hose on the shaft log just enough to allow the seal to seal on a flat clean surface. I have Tide seals sealing my shaft logs. Mainship 34 Pilot with a pair of 4LHA STP with 1.5 inch shafts. I purchased the boat in 2021. The engines had 850 hours at that time. Not that much use but 19 years of marine service. The seals have a serial number on them. Tides can tell you the year the seal was manufactured if you have a serial number. In my case the seal was manufactured in 2001. The seals did not leak. When I talked to the Tide representative he advised removal and full inspection of the seal housing and replacement of the silicone hose, clamps, and seals. He told me if the spare is still in place it would be a good idea to replace it also. Even though it has not been used the shelve life of the seal is 10 years. I was planning on replacing the 19 year old Cutlass bearings so ithis was a good time to do a full replacement of the Tide seal components. I pulled shafts to replace the seals components and cutlass bearings. You do not need to pull the shaft to replace but in my case it made it easier to remove and install cutlass bearings. While the shaft was removed I was also able to put the shafts in V-blocks and do runout checks and polish the shaft where the seal will ride on the shaft. I did reuse the Tide seal housing. I replaced the seal cap which was a newer design, the split washer, the spare shaft seal, shaft seal,blue silicone shaft log hose and clamps. After the replacement I have put 900 hours on the engines and 6500 miles under the keel and not a drop of water. The representative told mete Life expectancy of the seal and components is 10 years or 2500 hours of engine service. The most important preventive maintenance item to maintain the longevity is to make sure that the seal has good water flow for cooling the seal components.
