Honda BF8, BF9.9 and BF10 Outboard Motors Shop Manual., Page 348Get this manual
cINSPECTION DOWN RELIEF VALVE SEAT
Check the down relief valve seat, spring guide and spring for wear or damageReplace the down relief valve seat, spring guide or spring if damaged or worn
[2] SPRING GUIDE
DOWN RELIEF VALVE SEAT
CYLINDER, PISTON, FREE PISTON
Check the piston rod for damage and being bentReplace the piston rod with new one if necessaryCheck the inner and outer surfaces of the cylinder for damage and scratchesReplace the cylinder with new one if it is damaged or scratched