Yamaha F40BMHD Service Manual page 398

BRKT
POWER TRIM AND TILT UNIT
(8) Remove the reservoir cap
that fluid is up to the brim as shown.
Add fluid if the level is below the brim.
(9) Install the power trim and tilt reservoir
cap.
(10) Repeat the above steps two or three
times until the power trim and tilt fluid
is at the correct level.
7-24
E
2
and check