YPC

Hi Indatube !.........pleasure mate.....

I'm not sure if changing the Teflon for Brass will make all that much difference in a ******** - for most of it we are off the throttle, so the heat build up should not be all bad.
The overall seal is more important. If you wanted to remove the Teflon - you could simply slip the next size down of brass tubing into the ID of the stuffing tube.
The wind direction of the flex shaft unfortunately carries water up the stuffing tube - like the shavings from a drill bit, so the tighter the ID tolerance , the better.

When running a flex shaft their is a set up issue that you HAVE TO keep in mind.

Due to the flex shaft being made up of winding's, whenever the flex shaft is under torque ( acceleration) the shaft actually shortens in length as the flex shaft winds up. Like a spring shortening if you rotate it into its wind.

SO - if you are running a thrust washer against the face of the drive shaft housing - ALWAYS - ensure that you set your dog drive up with at least 2-3 mm of play between the thrust washer and the drive shaft housing face on the bench. - OTHERWISE - when the flex shaft is under torque, it will be pulling the thrust washer up hard against the drive shaft housing face on the one side and be tugging on the motor coupling on the other side, causing major drag and load.

This small over site has been the culprit of many broken cables and major power loss in various boat drive set ups.

If you get this right - you will have even more run time !!!

Bro ********
Share the STOKE !