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MitchK 12-01-2017 03:33 PM

Stuffing box adjustment
 
All,
I have been trying to eliminate or at least minimize water leakage into my N28-2. One of the larger leaks was the stuffing box. It has been leaking with the engine running as it is supposed to, and with the engine off. I checked it yesterday evening, and found it dripping at a rate of about one drop every 10 seconds. This was with the engine off. So I figured it was time to adjust it. I started adjusting in 1/4 turn increments. It took about 1-1/4 turns to stop the leaking. I could still turn the prop shaft by hand without too much effort, so the box should not be over tight. In the spring when I get ready for the season, I will adjust it again to ensure it is adjusted properly.

When we purchased the boat, the bilge below the stuffing box was wet, but there was no evidence of excessive leakage. I have put about 15 hrs on the engine since then, and the leak rate had increased significantly.

There appears to still be plenty of adjustment, so I am not too worried about it at this time. I will be pulling the boat out again in the spring, and I will repack the stuffing box at that time.

In going through the limited logs for the boat, there is no record of the stuffing box being serviced or adjusted in at least the last 10 years or so, so I was not too surprised it needed significant adjustment. I did find a partial package of teflon flax in the spares, so I at least have some idea as to what size and kind of flax is currently in the box.

On a side note, due to the limited access to the stuffing box, I had been trying to locate a set of stuffing box wrenches. I took a dial caliper and measured the two nuts, and found the large one to be 2" and the small one 1-3/4". Locating the 2" was easy, locating the 1-3/4" was very difficult. No one listed one in the smaller size. I finally stumbled across Catalina Direct, and they listed a wrench kit that had the correct size of wrenches. So I ordered a set. They were not cheap, but they are very good quality wrenches, made by PROTO. Anyway, I did have to open the 1-3/4 up just a hair for it to fit properly. They work great. Just the right size for the limited room available to work in.

Mitch

boatpoker 12-01-2017 04:29 PM

Re: Stuffing box adjustment
 
Make wrenches out of 3/8 plywood, take to local foundry and they will sand cast them in bronze for about $20.
Thats' how I got mine.

Capt Len 12-01-2017 08:14 PM

Re: Stuffing box adjustment
 
Living and teaching metal work in a fishing community a popular class project was stuffing box wrenches. Hacksaw and file 1/4 steel plate. Even an adult could do it.

MikeOReilly 12-01-2017 09:08 PM

Re: Stuffing box adjustment
 
I was going to say that 1 drop every 10 seconds at rest is too much, but nothing to be too concerned about, but then I see you had to put on 1 1/4 turns. In my experience (which is limited), thatís quite a lot. When Iíve made adjustments it has always been much smaller increments. So I guess it was definitely time.

For wrenches weíve got an aluminum pipe wrench and one of these adjustable. But I love your idea BP. Iíll have to look into it.

https://images-na.ssl-images-amazon....L._SL1500_.jpg

MitchK 12-02-2017 12:50 AM

Re: Stuffing box adjustment
 
Mike,
I don't have a lot of experience with stuffing boxes in general, so I took it slow and easy. I actually did five separate adjustments. Roughly 1/4 turn per adjustment. The first 1/4 turn slowed the drip down to approx. 1 drop every 18 seconds. The second slowed it to 1 drop every 30 seconds. The third, 1 drop every 45 seconds. The fourth. 1 drop every 1min 20 seconds, and finally the fifth, it sat for at least a good 15 minutes, and did not drip. For each of these adjustments, I verified the time between drips at least a couple of times to make sure I did not tighten it too much. I will re-do the adjustments in the spring before I take it out for the first run of the year.

Nice wrench, I have seen something like that in the past. Looks like it would work well.

Mitch

JimsCAL 12-02-2017 09:33 AM

Re: Stuffing box adjustment
 
I also am surprised that it took over 1 full turn to get from a drop every 10 seconds to stopped. But you tightened it gradually, observing the change at each adjustment, so you did it correctly. The thing to check is to verify that you get a slow drip when running the engine and that the stuffing box stays cool.

MitchK 12-16-2017 12:57 PM

Re: Stuffing box adjustment
 
All, quick follow up of the stuffing box. Was on the boat a couple of evenings ago. Checked the bilge, and it was bone dry. Checked the plastic lid I had placed under the stuffing box so I could get a better idea as to the leak rate, and it too was dry. If there had been any additional leakage, I would have seen it in the plastic lid. Anyway, come spring when I get it ready for the season, I will loosen the adjustment, start the engine and while in gear, adjust if for 3-4 drips a minute when running. I will also check the temperature of the stuffing box to make sure it is within spec.

Mitch

contrarian 12-16-2017 01:40 PM

Re: Stuffing box adjustment
 
Sorry Mike but those adjustable plumbing spanner wrenches are a poor choice for stuffing box nuts. I tried those one time because Don Casey recommended them, I lost all confidence in anything he said after that.

I do like the idea of the 1/4" plate Capt. Len but seriously, your'e going to cut it with a hacksaw and a file? How many months does that take ? Most local fab shops will at least have a plazma cutter. Some will have computerized plazma cutters and some will have precision water jet cutters.

Mitch, I think you made a good choice buying the proper tools for the job. Kudos Dude ;)

Capt Len 12-16-2017 04:59 PM

Re: Stuffing box adjustment
 
Packing will tend to harden over time , especially if flax/tallow and ever been heated. Once tightened to no drip for the winter may not rebound in the spring. As for making the wrenches I was interested in the concepts of layout,centerpunching ,drilling and cutting, filling to a line, pride in a finished useful product.These are learned skills that may be beyond the average boater .

Eder 12-16-2017 05:28 PM

Re: Stuffing box adjustment
 
Old boat tech in Port Townsend showed me how to adjust any stuffing box frozen or not...tap the lock nut a couple blows on the high side of the nut with a 2lb mallet. Turn packing nut by hand to snug...snug lock nut and 2 taps with 16oz hammer.Done...15 seconds once you practice.


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