Honda BF9.9A-BF15A Outboard Motors Shop Manual., Page 75Get this manual
HONDA BF9.SA-BF15A
5) Make light pass with 4' cutter remove any possible 5
burrs the edges the seat
6) resurfacing the seats, inspect even valve settingA Prussian Blue compound erasable felt-tipped marker the valve facesInsert the valves, and then lift them and snap the closed against their seats several timesBe sure the valve does rotate the seatThe seating surface, as shown by the transferred marking compound, should have good contact all the way around7) Lap the valves their seats, using hand valve lapper and lapping compound (commercially available)