2001 Edition Yamaha F225A and LF225A Outboards Service Manual, Page 137Get this manual
Cylinder head 2Check the cylinder head warpage using straightedge and thickness gauge in six directions as shownReplace if out of specification
NOTE: The valve spring can be installed in any directionValve spring compressor 5: YM-01253 Valve spring compressor attachment 6: YB-06320 Cylinder head warpage limit: 0.1 mm (0.004 in) 3Compress the valve spring, and then install the valve cotter using thin screwdriver with small amount of grease applied to it