Success and a Mystery

I have finally been able to finish cutting through the shaft on my Minn kota Traxxis 80 trolling motor. This brings me one step closer to putting it into my 1910 power dory. The original motor was a low hp make and break gas motor—now we will be going electric.  Here are some pics;

 First attempt at cutting the shaft.  The tubing cutter did not have enough depth.  Needed a pipe cutter which I finally found at Essex Rental.  When I told the counterman what I was doing, he got the cutter and we went out to the truck and finished the cut—no charge. Thanks.

 Here is the finished product.  Now I need to bore a hole through for the clamp.  Should be a piece of cake.  Please notice the brown wire.  That is the mystery.  Why is it there?  What does it do?  The insulation has not been stripped, there is no connector on the end as they other two wires have.

 A closeup of the three wires above. I will neaten up the cut, but there are no rough edges, seems to be some sort of carbon fibre.  And, below, the motor in place with a temporary spacer.  I am counting on the bottom of the hull to act as a doelfin.  Waiting patiently for an answer from Minn kota on the brown wire.