TOHATSU MFS 8B Service Manual page 227

Pressing "DOWN" side of PT switch causes the PT motor (gear pump) to rotate counterclockwise.
Check valve opens to cause oil to flow from reservoir toward gear pump and spool valve. This oil flow shifts spool
valve upward to open up-pressure main check valve. Oil in the cylinder lower chamber is returned to gear pump, hydraulic
pressure of oil passage is increased to open down-pressure main check valve, and the oil flows into cylinder upper
chamber. As a result of the above operations, piston rod is pushed down to tilt down the outboard motor.
The oil in the cylinder lower chamber returns to gear pump through up-pressure main check valve.
Because of difference of capacity difference between cylinder upper chamber and lower chamber, oil of amount exceeding
upper chamber requirement returns to gear pump.
When piston rod is drawn-in completely, all of oil discharged from the pump returns from down relief valve to the reservoir.
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