HYDRAULIC CIRCUIT FOR MARINE PROPULSION DEVICE

PURPOSE: To quickly perform trim action by providing a second fluid conduit including a one-way valve to allow flow from a sump part to a pump and inhibit flow from the pump to the sump part, and a means to open one check valve in response to closure of the other check valve. CONSTITUTION: A hydraulic circuit is provided with a means 125 to open one of check valves 83, 103 in response to closure of the other of the check valves 83, 103. As a pump delivery port 57 is pressurized, pressure fluid seats the check valve 103 on a valve seat 121. This motion slidably displaces a push rod 135 to open the check valve 83 to assure a discharge passage for excessive quantity of oil leaving an endless rod 38 compared to quantity of oil getting into an ended rod of a trim cylinder/piston assembly 31. As another result, all the discharge quantity of a pump 53 is utilized for quickly performing trim action of a piston rod 36.