I've been having reoccurring issues with saltwater intrusion into my well-used (2,500 hours) SD-60.I too was told that the small grove that the shaft seals
have formed on the prop shaft was the likely cause. A new SD-60 prop shaft is around $900. Any suggestions and alternatives to solving this issue less expensively. I'm getting tired of paying to pull the boat
out of the water
to replace the shaft seals
every ~250 hours.
Sidenote: My "sense" is that the water
intrusion along the prop shaft can be exacerbated by 1) An out-of-balance prop zinc that did not wear evenly (it happened to me once), 2. My relatively heavy Flexfold prop. 3. Running at RPMs that have higher vibrations as others have mentioned above.