Bravo XR with -2 sport master lowers... The prop hub (bravo 1 prop) is grinding into the Bearing Carrier Retainer nut?? WTF... this happened on 2 of the three drives (both outside drives) one right hand and the other left hand rotation. The center drive is fine. I have blown up & wrecked (I thought) everything that could be on a Bravo XR... This is new to me.. Anyone have any ideas on what caused this? I replace gears & bearings every 25 hours or close too, and just discovered this little surprise .
Oh yes.... this now happened when I changed the lowers to the 17/18 gears to get a 1.25 overall gear ratio.

thicker prop spacer? i know alfalfas have a couple of diff spacers. these new lowers might need more spacer.

Small prop shaft with a large prop hub?

No, they have the big prop shafts.