Tightening the packing gland can be dicey and may take practice. What you want is for it to drip when the shaft is turning, and stop when it is not. Depending on how worn the packing material is it may not be possible, (time to repack). I often have to check packing boxes after using boat to make sure they stopped dripping. (a small tighten after done using the boat, then loosen back the next time I take it out). If tightening gland stops vibration something is wrong. See above. It sounds like your using the packing box for a cutless bearing.
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