8-21 POWER TRIM AND TILT
SHOCK ABSORBER CIRCUIT
( ) Shock valve
Should the lower unit strike an underwater object whilst in motion, the piston will rise abruptly, creating a
sudden high impact pressure in the upper cylinder chamber. The shock valve will then open, allowing oil
to flow into the area between the tilt ram piston and the free piston, thereby dampening (absorbing) the
impact.
( ) Return valve
When the point of impact has passed, propeller thrust and motor weight will force the tilt ram piston back
downwards. The oil from between the ram piston and the free piston is then expelled through the return
valve before flowing into the upper cylinder chamber.
Tilt rod
Upper cylinder chamber
Return valve
Piston
Shock valve
Free piston