I'm getting ready to motor out the Erie Canal so I changed the packing. I didn't know the size and used 3/16 but it didn't quite fill the gap between the nut and shaft so I cut one the size of the nut and another the size of the shaft so they'ed fill the gap.
Instead of going out and getting the correct size packing material? Why would you do that? Even the Gore stuff is only about $15 for enough to re-pack your stuffing box twice.
... now I have some bronze dust in the bilge drain as shown in photo.
Looking for suggestions as what is causing this...
Looks like a stainless shaft and bronze stuffing box. My guess: The packing material is bound-up on the shaft, is spinning/turning in the stuffing box, and eating your stuffing box.
... and what I should do to stop it.
Um... install propery-sized packing material?
I used syntek PTFE and lube.
"Lube?" PTFE packing material requires no "lube."
I have some more with me so I could change it out at the next anchorage ...
Insanity: Doing the same thing over and over, and expecting different results.
Suggest you obtain and install the proper
size packing material before you damage your stuffing box, your prop shaft, or both. (If you haven't already.)