Yamaha F100B F100C Outboards Factory Service Manual, Page 67Get this manual
Power trim and tilt unitLower unitGeneral Recommended gear oil: Hypoid gear oil SAE: 90 Oil quantity: F100B: 0.785 (0.83 US qt, 0.69 Imp qt) F100C: 0.670 (0.71 US qt, 0.59 Imp qt) 5Install the check screw, quickly install the drain screw, and then tighten them to the specified torqueCheck and drain screw: Nm (0.7 kgfm, 5.1 ftlb)
S60C3590
3If pressure drops below specification, check the drive shaft and propeller shaft oil seals for damage
Checking the propeller
1Check the propeller blades and splines for cracks, damage, or wearReplace if necessary