1998 Johnson Evinrude "EC" 25, 35 HP 3-Cylinder Outboards Service Manual, Page 286Get this manual
Sending Unit Adjustment [] 1The sending unit eccentric cam must be adjusted so that the gauge needle is aligned with the lowest gauge mark with the motor trimmed all the way DOWN
[]] rn 2Check .the gauge needle isengage trailering lock if above or below the lowest gauge mark Tilt engine UP and&
3To avoid personal injury, do not adjust the sending unit eccentric cam while the engine is being tilted
4When the motor is trimmed all the way DOWN, the sending unit lever touches the eccentric cam just forward of the top of the cam at about 5Loosen cam screw and rotate eccentric cam to adjust full down gauge positionIf the needle was above the lowest markmove the thick part of the cam TOWARD the contact point Tighten the screw, and recheck the gauge reading If the needle was below the lowest markmove the thick part of the cam AWAY from the contact point Tighten the screw, and recheck the gauge reading