Re: 1962 Johnson 3hp Seahorse

[David Stanton]

If the head gasket is bad, the head is likely slightly warped – which can cause headgasket breakdown between the two cylinders. To make it flat, spread out emory or wet/dry sandpaper on a solid very-flat surface (I use the flat steel table of an old tablesaw). Then rub the head on it until the sanding marks on the head are uniform, meaning it’s flat. Do not over-torque mounting bolts or warpage may occur again.
Dave