Honda Outboards BF40A/BF50A Service Manual, Page 422Get this manual
BF40A-BF50A 25) Tighten the outer tube guide to the specified torque using the lock nut wrenchTORQUE: 88 Nem (9.0 kgfem, 65lbf eft) 26)Tighten the manual valve securely[1LOCK NUT WRENCH 070PA-ZW40100
OUTER TUBE GUIDE
27) Apply rubber grease or ATF to new oil seal.Holding the oil seal with your fingers so that it shapes "U" and install it in the groove in the outer tube taking care not to damage the oil seal28)Apply ATF to new O-ring and install it on the outer tube guide
[2] Push in by deforming it lightly
Push in aslant
[l[ OIL SEAL