GFO repacking

[Paul45c]

I used the GFO goretex stuffing box packing that came so highly recommended here by several of the members. It was a fairly easy job to tackle, and my only question here has to do with getting the gland nut tension set just right. I did it wrong the first time, as I saw the warning about too much nut tension too late to save one shaft's packing. It got hot enough to cook off on the first seatrial and I limped her back into the dock and redid it promptly. No harm done. At least I had the process down from having just redone both shafts.

So, I've had the stuff in there and allowing a moderate drip (maybe 1 drip every 7-10 secs while running at 1850 rpms) to get it broken in some. I did a little tightening today and almost did a big "oh NO!" because my port gland got pretty darned warm again. It was a good time to stop and anchor up to let the family swim some, anyway, so I backed off the tension some and get the gland to loosen up slightly. Freshwater hosed it off to get it back to a cold temp and then an hour later tried it again. No probs, it was right back to a temp you could comfortably keep your hand on for as long as you like.

Soooo...it seems getting the tension down is more black art than science. I think I remember Karl saying he took a while to gradually get it tuned in to the point where it barely dripped at all. OK, I can play that way, if that's true. Anybody have a recommendation on how much to tinker with it and how? And what's a tolerable temp for the gland to operate at when you're stepping along on plane? Thanks.

 

[Genesis]

A little warm is ok. Hot is not.

If you get it dialed in, it will be engine room temperature when running along on step (that is, ambient) with almost no water coming off the spray shield (you do have one over the shaft, right? If not put one on!) and no dripping of any material amount at rest. I could leave the boat and come back a week later to find the same small amount under the log that was there when I left.

 

[Paul45c]

A little warm is ok. Hot is not.

If you get it dialed in, it will be engine room temperature when running along on step (that is, ambient) with almost no water coming off the spray shield (you do have one over the shaft, right? If not put one on!) and no dripping of any material amount at rest. I could leave the boat and come back a week later to find the same small amount under the log that was there when I left.

Oh yeah, I've got the spray shield. Never had enough water dripping through to worry about it, thank goodness!

Just how gradually and over how long a period would you say you need to make the minute adjustments, Karl? And what do you think is the target number of drips over a minute, say, while running?

 

[Genesis]

You won't be able to see the drips while running when set correctly.... they're there, which is why you want the spray shield....

Run it in for a good 8-10 hours of operating time before screwing with it, and then make VERY SMALL adjustments and use it that way for another day.

 

[Nonchalant1]

I repacked with GFO and adjusted it over the summer season by gradually tightening as it adjusted itself. Adjusting does seem to be more of a black art because it's done by turning one or two faces of the nuts. If you tighten one 2 faces and nothing happens, do the other one 2 faces, back and forth.

I adjusted it to one drip per second at the dock at first, ran it 2 hours or so, adjust it to one drip per 5 seconds at the dock, ran it for a cruise of 2 to 6 hours whenever I went out again, adjust it back to one drip per 5 to 10 seconds. Then I adjusted it to one drip per 15 seconds and let it go for 10 to 15 hours of cruising. When I went back to adjust it again, it had reduced by itself to one drip per minute on one side and no drips at all on the other side (I can't explain this). It now drips almost zero at the dock or cruising and it's cool (engine room temp or less) when cruising all day.

BTW - I used 3 rings of GFO on my 2" shafts. More will fit in, but it makes it harder for the water to move through and cool it. I believe that's why the GFO comes in the lengths it does (one ppack does 3 rings). Also, you have to make really sure you got all the old packing out. I had one side overheat when I first did it and I redid that side and found old flax strings in a wad up near the deep end of the gland at the shaft. Those flex corkscrew packing pullers are great!

Doug Shuman

 

[the kuz]

When re-powered we kept the stuffing boxes and repacked with GFO. Also had cooling water lines (with cross over) run from the motors like you would do for dripless seals (drilled/tapped stuffing box housings) . 450 hours, no adjustments, no noticable drips, no spray shields, cool to the touch. Regards, Bob K