2000-2005 Yamaha F40B Outboard Service Manual, Page 282Get this manual
CHECKING THE WATER PUMP HOUSING Check: Water pump housing Cracksdamage 7 Replace
CHECKING THE IMPELLER AND INSERT CARTRIDGE
Check: Impeller Insert cartridge Cracksdamage defective parts
Replace any
CHECKING THE WOODRUFF KEY
Check: Woodruff key Damagewear
Replace
INSTALLING THE IMPELLER AND WATER PUMP HOUSING
Install: Impeller