For a while I’ve had a knocking noise when at low idle after the engine repower. After a lot of trips to the bilge trying to figure out what’s going on, I found that the PSS Dripless Shaft Seal was dripping. This has been ongoing now for 6 weeks or so. The seal is a stainless steel disc attached to the propeller shaft near the transmission, and a matching set of bellows and a carbon disc that pushes up against the steel disc. The stainless steel disc rotates with the prop shaft, while the carbon disk stays still, and is pressed against the steel disc. Water lubricates the carbon disc so that it doesn’t heat up, and the whole thing is supposed to provide a dripless solution that is better than a stuffing box because of low maintenance.
This is a companion discussion topic for the original entry at https://seabits.com/knocking-noise-partially-solved-pss-shaft-seal/