Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-42794--1, Page 135Get this manual
9Remove water pump base and gasket10Inspect base and replace if cracked distorted or melted Bearing Carrier and Propeller Shaft Removal
IMPORTANT: For proper retention between housing and cover nut, it is recommended that PLASTIC cover nut (if equipped) NOT be reusedReplace as required