2007-2009 Yamaha F15/F20 Outboard Service Manual, Page 291Get this manual

2007-2009 Yamaha F15/F20 Outboard Service Manual, Page 291

6) SPECIAL COATED STEEL GASKET The special adhesive is given onto the steel gasket for cylinder head to obtain better sealing ability of mating surface, which can protect the surface corrosion due to penetrating water
Fig9 Head gasket with adhesive

7) STURDY TOP COWL