2003 Johnson ST 6/8 HP 4 Stroke Outboards Service Manual, PN 5005471, Page 37Get this manual
INSTALLATION AND PREDELIVERY OUTBOARD MOUNTING
OUTBOARD MOUNTING
WARNING
Centering the Outboard
Locate the centerline of the boat transom as it relates to the hull (bottom) of the boatUse straightedge to draw line connecting the port and starboard chinesThe chines should be used as reference points for determining the centerline of the hullUse framing square to accurately place line on the transom The centerline of the hull should be in line with the keel of the hull and perpendicular to the midpoint of the line connecting the port and starboard chines
The outboard must be correctly installedFailure to correctly install the outboard could result in serious injury, death, or property damage
IMPORTANT: Follow all directions carefullyThe outboard's warranty will not cover product damage or failure resulting from incorrect outboard installation
WARNING
Even if equipped with clamp screws, the outboard must be bolted to the boat to prevent it from "working off the transom" during operation