Yamaha Outboard Motors Factory Service Manual F6 and F8, Page 162Get this manual
INTAKE SYSTEM INSTALLING THE INTAKE MANIFOLD
Install: Intake manifold
Tighten the intake manifold mounting bolt in sequence and two steps of torqueIntake manifold mounting bolt: 1st: 6.0 (0.6 kfg m, 4.4 ft lb) 2nd: 12.0 (1.2 kfg m, 8.8 ft lb)