2009 Yamaha F40 Outboard Service Manual, Page 230Get this manual
Exhaust cover 4Tighten the exhaust cover anode plug to the specified torque5Install new gaskets and the exhaust cover plugs m, and then tighten the exhaust cover plugs to the specified torque6Install new gasket and the exhaust cover plug o, and then tighten the exhaust cover plug to the specified torque 0 4