9-16 POWER TRIM AND TILT
Upper cylinder chamber
Lower
cylinder
chamber
"UP" pressure main check valve
"DOWN" pressure
main check valve
Spool valve
Check valve
Gear pump
PTT motor
Oil reservoir
Tilt rod
Piston
"DOWN" relief valve
TRIM/TILT “DOWN” CIRCUIT
The electric motor is operating in a counterclockwise direction. Check valve B will open, allowing oil to flow
from the reservoir to the pump. Oil flow from the pump enters the spool valve, moving it to the right, thereby
opening the “up” pressure main check valve. Oil from the lower cylinder chamber will go through the “up”
pressure main check valve to the pump.
Pressure built up by the pump will open the “down” pressure main check valve and oil will enter the upper
cylinder chamber. The piston will retract (move inward), which will tilt the outboard down. Oil in the lower
cylinder chamber is returned to the pump through the “up” pressure main check valve.
When full “down” position is reached, continued operation of the “down” relay will have no effect, as pump oil
flow will be returned to the reservoir through the “down” relief valve.
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