Honda Outboards BF40A/BF50A Service Manual, Page 406Get this manual
BF40A-BF50A 12) Remove the bottom piece from the cylinderRemove and discard the a-ringReplace the a-ring with new one during reassemblyClean the threads of the bottom piece14) Remove the piston and free piston from the cylinderRemove and discard the a-rings and discard themReplace the a-rings with new ones during reassembly
[1] BOTTOM PIECE
[2] CYLINDERPISTON ASSY[3] O-RING