Honda BF35A-BF45A Outboard Motors Shop Manual., Page 404Get this manual
BF40A.B FSOA 6) Remove the outer tube guide using the lock nut wrenchRemove the O-rings from the outer tube guide and discard themReplace the O-rings with new ones during reassembly
1I LOCK NUT WRENCH 07OPA-ZW40100
OUTER TUBE GUIDE
7) Remove the valve body and cylinder assembly from
the vise