2004 SR Johnson 2 Stroke 9.9, 15, 25, 30 HP Outboards Service Manual, Page 38Get this manual
INSTALLATION AND PREDELIVERY TRANSOM MEASURING AND DRILLING
TRANSOM MEASURING AND DRILLING
Inspect Transom Area
Transom Clearances
Make sure the transom and splash well area provide adequate outboard clearancesConfirm that the proposed mounting hole locations will provide adequate clearance for mounting bolts and washersCheck the inside area of the transom for obstructions prior to drilling mounting holes
Use framing square to accurately place line on the transomThe 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
Water Flow