Yamaha F100B F100C Outboards Factory Service Manual, Page 259Get this manual
Bleeding the power trim and tilt unit (F100B) Built-in
1Loosen the manual valve by turning it counterclockwise until it cannot be turned further8If necessary, add sufficient fluid of the recommended type to the correct level
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2Fully tilt the outboard motor up, and then release it and let it lower by its own weight four to five times3Tighten the manual valve by turning it clockwise4Let the fluid settle for minutes5Push and hold the power trim and tilt switch in the up position until the outboard motor is fully tilted up6Support the outboard motor with the tilt stop lever, and then let the fluid settle for minutes