Honda BF20 BF2A Outboard Motors Manual, Page 38Get this manual
HONDA BP20-BFSA
VALVE SEAT WIDTH
Measure the valve seat width-
STANDARD 0.7 mm (0.028 in)
SERVICE LIMIT 1.0 mm (0.04 in)
If the valve seat width under the standard, or over the service limit, recondition the valve seat
dRECONDITIONING
VALVE SEAT RECONDITIONING
Resurface the valve seat with seat cutter, removing only enough material to produce smooth and concentric seat
CUTTER HOLDER NO07781-0010100