2004 SR Johnson 4 Stroke 9.9-15HP Outboards Service Manual, Page 118Get this manual
POWERHEAD INSPECTIONSERVICING
Valve Head Thickness
Measure: Valve head thickness (j)
Vernier calipers
Valve head thickness Service limit: IN and EX 0.5 mm (0.02 in)
If exceed service limitReplace
Valve Seat Width
Measure: Width of seat contact 1Coat valve seat evenly with Prussian blue (or equivalent)2Install the valve into cylinder head3Put the valve lapper on valve
Valve lapper