Honda BF8, BF9.9 and BF10 Outboard Motors Shop Manual., Page 354Get this manual
2) Apply ATF to two new O-rings, and install the O-rings in the valve bodyInstall the smaller O-ring in the lower groove and the larger O-ring in the upper groove of the valve body 11 1
[3] VALVE BODY
3) Apply ATF to new O-ring and backup ring, and install them on the free piston[I] FREE PISTON
[2] BACKUP RING
2.4 27.7 mm