Yamaha 115-225 HP Outboards Service Manual, Page 190Get this manual
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HYDRAULIC FLUID PRESSURE TEST Drive the motor to check trim and tilt up and down operation and fluid leakage
POWER TRIM AND TILT UNIT
1) Set the manual valve to the manual tilt positionNOTE: _ Turn the manual valve toward the manual tilt until it stops2) Connect the pressure gaugeNOTE: _ Only set of hoses is available so that both of the trim and tilt pressures can not be measured at the same time
3) Connect the leads to battery to check the fluid discharge pressure during upoperationTrim and tilt up Blue (+) Green- )