A few weeks ago out of the blue I heard a rattling/ticking sound coming from my Minn-Kota 55lb. thrust transom mount electric motor (purchased in 2014) and after taking off the prop (though maybe line, weeds, gunk under the prop), and taking the two long screws out from the motor section, found that the issue was that the magnetic portion of the motor had a portion (about 1.5" by 1.5") that had broken off and must have been rubbing upon rotation (power on and also in reverse).  Should I epoxy this portion back on or just leave it go?  Everything was put back together without the small piece that was broken and the sound is gone and everything seemed to function just fine when tested on the marine battery.  Will I lose any overall power on the lb. thrust since a small portion is missing?  Thanks for any/all help!  Best wishes on the water!

You will probably be better off just leaving it out.  If you epoxy a broken piece back, it can actually make the magnet weaker because the two fields are going to be reversed were the break is at.  You might see if MK sells a whole replacement magnet that you could epoxy in to replace the broken one.

As for power loss, there will probably be a little but doubt it would be enough you would ever notice.