1986+ Mercury 6/8/9.9/10/15HP 2-stroke Factory Service Manual, Page 44Get this manual
OUTBOARD INSTALLATION
Installing Outboard
1Measure the transom height of your boatThe boat bottom should be aligned or be within 25 mm (1 in above the anti-ventilation plate of the outboard2Place outboard on center line of transom
025 mm (0in)Anti-Ventilation Plate 3Tighten transom clamp handles4To prevent loss of outboard overboard, fasten outboard by drilling two 7.9 mm (516 in holes through the transom using transom clamp holes as templateFasten with two bolts, flat washers and locknutsUse marine waterproofing sealer in holes and around bolts to make the installation water tight