Honda Outboards BF40A/BF50A Service Manual, Page 409Get this manual
BF40A-BF50A 9) Prepare piece of piano wire of 1.5 mm in diameter as shown7) Set the prepared wire in the holes in both sides of the sleeve as shown, and secure the wire by inserting the 10 mm bolt into the sleeveRemove the sleeve from the valve body by pulling the wire with care not to damage the valve bodyRemove the O-ring from the sleeve and discard itReplace the O-ring with new one during reassembly3mm (0.120.15 in) [1] About 50 mm (1.0 in)