Honda Outboards BF40A/BF50A Service Manual, Page 405Get this manual
BF40A-BF50A 10) Hold the bottom piece in vise with shop towel or soft jaws as shown and loosen the outer tube using the lock nut wrench, then remove the cylinderpiston assembly from the viseCAUTION:
[1] LOCK NUT WRENCH 30 40 07916-9690000
Take care not to tighten the vise too tight as it damages the bottom piece
[2] OUTER TUBE