Stuffing Box question

[Harry2k]

I know there are a number of threads on prop stuffing box issues but I have reviewed them all and can't find an answer to this one. Please excuse me if I missed it?
Is it common for a stuffing box to leak - drip roughly every 8 seconds - when engine is first turned over after sitting at moorage for winter months?
Background:
I have a SJ 28 with a Yanmar 2GM20 engine. Boat is sailed and moored in the Seattle area. I had a new shaft, coupler and stuffing box installed in 2017. The yard that did the work used Gore TexGFO packing and it performed beautifully. Two years ago a had the boat hauled at the same yard and while on the hard I had them pull the used packing and replace it with new GFO. A simple adjustment after splash and it again performed well over the last two seasons. I generally use the boat year round but was unable to this year. She sat at the dock from mid October through the end of Feb. I have finally gotten back on track and after doing some routine Spring maintenance, I turned the engine over. Started like a champ, running great no unusual vibration, etc. After idling for 10 minutes I checked the engine compartment and found the leak mentioned above. I don't recall this ever happening before. I shut the engine down and decided to do some research before messing with stuffing box adjustments. I'm wondering if this is a common occurance and a matter of the packing needing to absorb some water and come up to temp after sitting so long or if I should just proceed with standard adjustment of the packing gland?

[wholybee]

Stuffing boxes drip while the shaft is turning. If they don't, they will overheat and could cause wear on the shaft.

A drip every 8 seconds is maybe on the high side, but reasonable. I would not touch it yet. The goal is to have it not drip when the shaft is not turning, and drip a couple times per minute when turning. If it starts to drip when the shaft is not turning, then tighten it until it just barely doesn't drip, and check that it still drips when turning.

[Harry2k]

Yes, but this leak was with the engine in neutral, prop not turning. Definitely not leaking when engine is shut down.

[wholybee]

That does sound strange. There is no harm tightening it a bit to stop it, then just check that you get a couple drips while it is turning.

[Harry2k]

Thanks. That's what I'm considering but I was curious if that kind of leak could be caused by the boat sitting idle so long in winter.
Guess I,'ll just tighten and monitor.

[skipperpete]

Maybe check the alignment, yanmar mounts are very soft and settle over time OR even increase in size and push the engine out of alignment. The RH front mount is usually the culprit and the change is often caused by fuel from the bleeder screw on the injector pump, its surprising how little it takes to bulge the rubber element. Don’t let diesel fuel get on Yanmar mounts.

[Rustic Charm]

GFO is good packing. It should not be dripping at all when idle. Do the compression up until it stops leaking. When running, I keep a close eye on the temperature at the packing with a temp gun thingy.

[Harry2k]

Originally Posted by skipperpete

Maybe check the alignment, yanmar mounts are very soft and settle over time OR even increase in size and push the engine out of alignment. The RH front mount is usually the culprit and the change is often caused by fuel from the bleeder screw on the injector pump, its surprising how little it takes to bulge the rubber element. Don’t let diesel fuel get on Yanmar mounts.

Thanks SkipperPete I hadn't thought to check alignment as vibration seemed normal Will do that this weekend.

[Harry2k]

Thanks Rustic Charm, I usually set the compression for zero leak at idle and 2 to 3 drips terminate when turning.
I will do that as planned and check alignment as SkipperPete suggests.
Thanks all