Honda Outboards BF40A/BF50A Service Manual, Page 119Get this manual
Quality of the image is intentionally reduced!
HONDABF315A o4!5A 95 mm6 40 mm FLANGE SOLT
LOCK NUT WRENCH
07LPB-ZV30100
07916-7500000
3) On installation, replace the lock nut with
a new one