Honda BF20 BF2A Outboard Motors Manual, Page 37Get this manual
HONDA BFSOBFSA
cINSPECTION
VALVE SPRING FREE LENGTH
Measure the free length of the valve springs
STANDARD 27.1 mm (1.07 in)
SERVICE LIMIT 25.0 mm (0.98 in)
Replace the springs if they are shorter than the service limit
VALVE STEM O.DInspect each valve for face irregularities, bending or abnormal stem wearReplace the valve if necessaryMeasure and record each valve stem O.DSTANDARD IN EX SERVICE LIMIT
5.490 mm (0.216 in) 5.445 mm (0.214 in)
5.45 mm (0.215 in) 5.40 mm (0.213 in)
Replace the valves if their O.Dis smaller than the service limit
VALVE GUIDE I.DNOTE:
Ream the valve guides to remove any carbon deposits before measuringMeasure and record each valve guide I.D