Abstract: A hydraulic tilt system for a marine propulsion includes an improved construction for ensuring a reliable tilting operation and holding the marine propulsion at a tilted position securely. The hydraulic tilt system has a pair of shuttle valve assemblies which can selectively deliver working fluid to one of upper and lower chambers in a tilt cylinder housing from a fluid pump or return it to the pump from the other chamber. The respective shuttle valve assemblies include shuttle pistons slidably supported in shuttle housings. Only one of the shuttle pistons has a seal member therearound. A small gap is, therefore, formed between an outer surface of the other shuttle piston and an inner surface of the shuttle housing.

Abstract: A tilt and trim adjustment mechanism includes an improved arrangement of a powering unit in order to reduce the size of the assembly, including the size of the hydraulic motor used to raise and lower the outboard motor. The powering unit is mounted on a lower end of the hydraulic motor so that the brackets of an associated coupling assembly (i.e., swivel and clamping brackets) do not have to be widened in order to accommodate the tilt and trim adjustment mechanism. In addition, the hydraulic motor can be arranged to position the motor at the center of the assembly. By having the hydraulic motor act at the center of gravity of the assembly, a smaller hydraulic motor can be used. In addition, the tilt and trim adjustment system includes an improved manual override valve that includes a push button actuator. No tools are required to open the valve. In addition, the button is conveniently located on the powering assembly to be accessible for manually lowering the outboard motor.