Honda BF20A-BF25A, BF25D-BF30D Outboard Motors Shop Manual., Page 110Get this manual
HONDA 6FEOAmESA
VALVE SEAT WIDTH
Measure the valve seat widthSTANDARD IN1 EX 0.9- 1.1 mm (0.0350.043 in) SERVICE LIMIT 2.0 mm (0.08 in)
If the valve seat width is under the standard, or over the service limit, recondition the valve seatSee page 10-12
ROCKER ARM SHAFT O.DMeasure the O.Dof the rocker arm shaftSTANDARD
7 2.96212.980 rnrn (0.5103-0.51 in)
SERVICE LIMIT 12.92rnrn (0.509in1
Replace the rocker arm shaft if its O.Dis smaller than the service limit