2005 Yamaha F90TR 90HP Outboards Factory Service Manual, Page 128Get this manual
Lower unit
Removing the water pump and shift rod
1Remove the water pump housing and impeller2Remove the Woodruff key3Remove the outer plate cartridge and oil seal housing4Remove the shift rod assembly 1
Checking the water pump and shift rod
1Check the water pump housing for deformationReplace if necessary2Check the impeller and insert cartridge for cracks or wearReplace if necessary3Check the Woodruff key and the groove on the drive shaft for wearReplace if necessary