1998-2006 Yamaha F20/F25 Outboards Service Manual, Page 165Get this manual
CAMSHAFT AND VALVES
5Measure: Valve stem runout Out of specification valve
Replace the
Valve stem runout limit: 0.016 mm (0.0006 in)
When replacing the valve always use new valve guide and valve seal
Valve spring inspection 1Measure: Valve spring free length Out of specification Replace the valve springValve spring free length: 37.8539.85 mm (1.4911.569 in)