Honda BF15D BF20D Outboard Motors Shop Manual., Page 167Get this manual
2OIL PUMP aDISASSEMBLY
I) Remove the three 35 mm flange bolts and remove the
oil pump assembly and oil pump O-ringDiscard the 0ring, replace with new one when reassembly2) Remove the two 12 mm flange bolts and remove the oil pump cover and cover O-ringDiscard the O-ring! replace with new one when reassembly3) Remove the inner rotor! pump shaft, 15.8 mm pin and 11 mm thrust washer
4) Remove the outer rotor