another stuffing box question - is it possible to over-grease?

[ChattingLil]

Unfortunately for us we haven't been able to start the engine and run under load for over six months. Did so this weekend and now the gland is leaking quite a bit. 2 drips per second.

I screwed down the grease, but it's still dripping. Googled some info on possibility of changing it while we are it the water (not feasible for us I think) but I saw on one clip someone suggesting that they may have over-greased it. Is that possible/a risk?

 

[Tranona]

Yes. Grease is not there for the seal when the engine is running, but to stop water leaking out when at rest. If you over grease it fills the stern tube and limits cooling of the seal and can lead to increased wear. If the seal drips under way it needs adjusting, or if this does not work then repacking.

 

[ghostlymoron]

As suggested above, the way to stop drips is to compress the packing more. Nip the adjusting nut up a bit till you reduce it to one drip per minute when under way. Too tight and it will overheat - you should be able to keep your hand on it without pain. You can feel friction on the shaft when it's about right.
If it won't tighten up, you'll have to replace the packing which should be done out of the water for the first time at least.

 

[Spyro]

If you have tightened up the adjuster as far as you can It's possible to add another ring or 2 of packing without pulling out the old stuff which would require a lift out or dry out. Good info here http://www.tb-training.co.uk/10sgear.htm

 

[LittleSister]

Good info here http://www.tb-training.co.uk/10sgear.htm

That is good. Thanks for the tip.:encouragement:

 

[AndrewB]

There's usually four rings. Replacing the top two while on the water should be straightforward enough, you'll have some leakage during the operation of course but it shouldn't be uncontrollable. Hook them out with a bradawl or a sharpened piece of coathanger wire. Two good new rings will be enough to keep the leaks under control for the time being. (In my experience, Spyro's suggestion to just add an extra ring sounds good but is unlikely to work in practice).

The rate of leakage you have suggests not just that the old ones are worn but the wrong size packing may have been used. Try a slightly larger size - get a ring out and measure it, there will be time to get to the chandlers and back with the new packing before you sink!

After refitting, the advice given by Ghostlymoron above is good: tighten up the bearing until it just stops leaking when the propshaft is stationary, check that it does not get more than warm when in use.

Its news to me that you can over-grease this bearing. But grease alone will not control leakage if the packing is worn out or inadequate.

 

[Ian_Edwards]

+1 for Tranona's post, I manage to over grease a conventional stuffing box, on the 1st boat I owned with an inboard engine.
Over time the grease fill the stern tube, block the water circulation and if you seriously over do it (as I did), it'll get into the cutless bearing, where it will trap grit and sand and wear the shaft. It's also very difficult to remove water proof grease from the stern tube, as I found out.
The real answer is to fit one of the many shaft seals available, then you don't get any drips.

 

[Billjratt]

Has the seal worked OK previously? If so, maybe it's just dried out a bit while ashore. You don't mention what the seal material is, but since it has a greaser I assume it's the old-fashioned stuff. The greaser should link to a grooved spacer midway between the packing layers so the grease spreads inboard and outboard to all the layers. If you add extra packing or have over-compressed, the spacer may no longer be in line with the nipple and the grease may not be distributed properly. There is new magic packing available - looks like black plastic... probably impregnated with molybdenum (oh no - a metallurgist will cry incompatibility) that self-lubricates and doesn't drip much at all - I like it. You can do quite a lot of fiddling with the boat in the water, even if you have to use plasticine as an interim sealant, Checks the bilge pump as well..

 

[ChattingLil]

just an update.
Turns out we seem to have a old home made DIY stuffing box as I wasn't able to identify it and our very useful local expert came over to look and he couldn't ID it either - so it looks DIY. However, after applying some eberspacher magic we have managed to put another couple of turns on the greaser and the drip has slowed down to less than 1 a minute. We are in the water and haven't been able to run the engine for ages because HWMO was working on and didn't get around to finishing it until the weekend!. Hopefully, it was all just dried out and hard and we don't have an immediate problem. I do want to get lifted and have it replaced though - it's not good that we can see how to service it or replace the packing.

thanks for all the advice and input.

 

[ghostlymoron]

What's the eberspacher got to do with it?
As said earlier, adding grease won't have much effect once the shaft starts rotating so I suggest you try adjusting the packing nut to at least get a bit of 'drag' on the shaft.

just an update.
Turns out we seem to have a old home made DIY stuffing box as I wasn't able to identify it and our very useful local expert came over to look and he couldn't ID it either - so it looks DIY. However, after applying some eberspacher magic we have managed to put another couple of turns on the greaser and the drip has slowed down to less than 1 a minute. We are in the water and haven't been able to run the engine for ages because HWMO was working on and didn't get around to finishing it until the weekend!. Hopefully, it was all just dried out and hard and we don't have an immediate problem. I do want to get lifted and have it replaced though - it's not good that we can see how to service it or replace the packing.

thanks for all the advice and input.