3mm to 3/16

Aquacraft built the bearing into the propshaft .1565" rides in a 1/8" stuff tube then drops down to 3mm with threads for a small prop. The prop shaft is only 2.5" with the .123"Flex cable attached the assy is 12 inch,total. I,have doubled the output power of the boat "from 1800kv to 3500kv and...