2007-2009 Yamaha F15/F20 Outboard Service Manual, Page 174Get this manual
Lower unit Recommended gear oil: Hypoid gear oil API: GL-4 SAE: 90 Oil quantity: 300 cm3 (10.14 US oz, 10.58 Imp oz)
7Install the propeller and propeller nut 0Place block of wood between the anti-cavitation plate and propeller to keep the propeller from turning, and then tighten the nut to the specified torque
D S6AG6440
S6AG6720