Yamaha Marine Outboards F4A/F4 Factory Service Manual, Page 198Get this manual
CRANKCASE, CRANKSHAFT AND CAMSHAFT
Oil seal housing assembly 1Install: 9Oil seals (housing lower and center)
Use the special tool, to install the two oil seals (one by one)Driver rod: YB-0622990890-06652 Needle bearing attachment: YB-0623090890-06649
2Install: 9Oil seal (upper housing)