Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-42794--1, Page 381Get this manual
5Remove main body (a) by tilting the top of body out first from tank (b) Main Body Installation
1Install gasket (a), if removed, and collars (b) in gasket main body (c)
NOTE: Gasket must be replaced if it shows signs of deterioration such as cracking, swelling, sagging or discoloration 6If gasket is to be replaced, remove internal oil filterSee page 207Remove collars (a) and gasket (b)