Honda BF8, BF9.9 and BF10 Outboard Motors Shop Manual., Page 170Get this manual
VALVE GUIDE REAMING For best results, be sure the cylinder head is at room temperature before reaming the valve guides1) Coat the reamer and valve guide with cutting oil
r11 VALVE GUIDE REAMER
2) Rotate the reamer clockwise through the valve guide the full length of the reamer
3) Continue to rotate the reamer clockwise while removing it from the valve guide4) Thoroughly clean the cylinder head to remove any cut-
ting residue5) Check the valve guide bore; it should be straight, round and centered in the valve guideInsert the valve and check operationIf the valve does not operate smoothly, the guide may have been bent during installationReplace the valve guide if it is bent or damaged6) Check the stem-to-guide clearance(P10-14)