The required plug gap for a 25 hp Johnson outboard is .030 in.
Johnson 6hp spark plug gap
The plug gap for a 70 Johnson would be .035 - .040.
The 25 hp Johnson outboard runs a plug gap of .030 in.
The recommended plug gap for the 2000 model, 4 hp Johnson is .030 in.
The plug gap for a 94 model, 50 hp Johnson is .030-.035 in.
The required spark plug air gap for the 83 model, 15 hp Johnson is .030 in.
The listed air gap for this engine is .030 in.
1984 Johnson 6 HP
.030
.030
.030 .030
The correct plug gap for the 1971 model, 6hp Johnson outboard, is .030-.035 in. It requires a Champion J6J, or NGK B6S.