2004 SR Johnson 4 Stroke 9.9-15HP Outboards Service Manual, Page 113Get this manual
POWERHEAD INSPECTIONSERVICING
INSPECTIONSERVICING
NOTE: If any component is found to be excessively worn, cracked, damaged or defective in any way, it must be replaced
Cylinder Head
Decarbon: Combustion chamber wall Measure: Cylinder head distortion (gasket surface)
Thickness gauge Straight gauge
Cylinder head distortion Service limit: 0.10 mm (0.004 in)