No idea on motor serial number other than it is a 20 inch 2.4 200 Mercury. Found more water than oil in my 2.4 lower unit. Pulled bearing carrier to replace seals and the roller bearings fell out and found out the reverse gear bearing is shot. Planning on doing the water pump assembly base included and impeller. If I can figure out how to pull the roller bearings and replace, as well as the revers gear bearing in the carrier do I need to reshim the carrier or just put back in and torque back to 210 lbs.