prop shaft seal

[knotflying]

Your's is somewhat different than mine, but same principal. It does look like burned material. Just to review a few things. I assume you used 3 pieces of material with a bias cut on each piece to cause an overlapping joint and you staggered the joints at about 12, 4 and 8 o'clock? Did you pack each piece in tight before inserting the other? Did you keep the initial tightening somewhat loose ( letting more water through) until the packing wore in and seated properly. This requires running a bit and slowly tightening over time until drip comes at 20 second intervals. Are you getting water flow from the hose going into the barbed fitting on the shaft? I assume you are getting flow out of the barbed fitting when the hose is removed? Your temperature at the fitting should be about 10 to 15 degrees higher than water temperature. Drip should be once every 20 seconds when shaft it turning. For safety sake, I would do a replacement out of the water. It will work fine in the water if all is okay, but I wouldn't chance it.

 

[harry ames]

Poopsy is adjusted for no drips at the dock and one every 10 or 15 seconds while at speed. No heating detectable in the union while at speed. I've heard both arguments that there should be some dripping at the dock. I don't like that argument when I'll be away from the boat for any amount of time. I think dripping at speed is the key indicator. If Poopsy dripped a drop or two every once in a while at the dock, then I'd be okay, but I think I have the sweet spot where it is not dripping at the dock.

 

[asm777]

knotflying, the only thing we've done so far is replaced the 2 brass bolts, 2 washers and 4 nuts that allow for adjustment of the stuffing box seal. The packing material inside is the factory original and is going on 30 months of service. I've heard various different things ranging from packing material should be proactively replaced every other year to it's fine as long as there plenty of adjustment left.

Having never seen with my own eyes what packing material looks like (either fresh or burnt), I'm making an educated guess that that's what the black stuff I found lining the makeshift prop shaft cover is...

TugNuts is a wealth of information and glad for the community here. I'll also follow up with the factory and a local mechanic for some insights.

It's still unclear to me whether the packing material can be replaced with the boat in water or if it needs to be hauled out... some have mentioned possibly needing to pull the shaft!

 

[asm777]

Poopsy is adjusted for no drips at the dock and one every 10 or 15 seconds while at speed. No heating detectable in the union while at speed. I've heard both arguments that there should be some dripping at the dock. I don't like that argument when I'll be away from the boat for any amount of time. I think dripping at speed is the key indicator. If Poopsy dripped a drop or two every once in a while at the dock, then I'd be okay, but I think I have the sweet spot where it is not dripping at the dock.

Agree with this thinking. It shouldn't be leaking when the boat is sitting at the dock!

Another issue is, it doesn't seem like the adjusting hardware stays fixed. It seems that the vibrations from regular operation allow the adjustment to back out so that the shaft leaks and leaks after EVERY outing?

Unique to our situation, we had to have a transmission replacement which was done at the slip but required the engine to be manhandled around in the engine compartment. Is it possible that when the transmission was replaced, the prop shaft alignment wasn't 100% which might be the cause of our ongoing prop shaft leaking issued?

Any thoughts on whether these kinds of things can be checked in the water? I'm starting to think that a haul out is in order just to inspect to make sure everything is "tuned" correctly...

Then my question is, who runs point on making sure everything is functional? Unlike getting service for my cars, getting service on a boat seems to be a half dozen different companies each handling their own respective parts... but what happens when an issue is related to more than one company's systems? (Volvo engine vs shaft parts or Garmin autopilot tied in to steering system)

Sorry, now I've gone way off topic!

But appreciate the feedback!

 

[knotflying]

My thought initially was possible shaft alignment problem. I would check that. It is easy enough. Loosen the shaft bolts and ease a flat feeler gauge in one gap at the top next to a bolt. Then fit it in next to each remaining bolt the gap should be no different than 4/1000 of an inch among them.
Again replacing the packing in the water is not what I would do. If you have a problem then you have to start dealing with water infiltration.
As far as periods between changes; I had 1,400 hours on mine and 6 years. I can't see changing it unless there is no more adjustment left.
Not sure why your bolts are loosening up, but that tends to lead to vibration and again, shaft misalignment? On vibration prone fasteners it is common to drill a small hole on the edge of the nut (not passing thru the center but the side) and then inserting stainless wire through and twisting it and then twisting it around a stationery item. This prevents it from turning off. Or you could try a thread locking material.

 

[pohanian]

Does anyone know what size nuts are used for the prop shaft seal for a C30?? Are they SAE or metric?

 

[asm777]

Does anyone know what size nuts are used for the prop shaft seal for a C30?? Are they SAE or metric?

If you are talking about the nuts used to adjust the prop shaft seal drip rate, here's what I was told for our C30CB:

you need 2ea.of the following items #8,#7 and #6 and 2ea.of #3

#3 part number is 0094STUD2.50X0.38 STUD BRASS

#6 Part number is 0260S375 flate washer 3/8”

#7 Part Number 0250S375-16 Hex Full nut SS 3/8”-16

#8 Part Number 0252S375-16 Hex Jam nut SS 3/8”-16