1996-2005 Suzuki DF40, DF50 Four Stroke Outboard Service Manual, Page 173Get this manual
POWER UNIT 6-30 VALVEVALVE GUIDE Valve guide to valve stem clearance Using micrometer and bore gauge, take diameter readings on valve stems and guides to check guide to stem clearanceBe sure to take readings at more than one place along the length of each stem and guide09900-20205Micrometer