A marine propulsion device includes a support adapted to be attached to a boat hull and a propulsion assembly including a propeller adapted to be driven by an engine. The propulsion assembly is connected to the support for vertical pivotal movement relative thereto and a hydraulic tilt cylinder and piston assembly is connected at one end to the support and has a second end connected to the propulsion assembly. The piston is movable toward the other end of the cylinder when the one end is pressurized to tilt the propulsion assembly upwardly. At least one trim cylinder is fixed relative to the support and includes a trim piston reciprocally mounted on the cylinder and releasably engageable with the propulsion assembly. Actuation of the propeller while the propulsion assembly is tilted upwardly is operative to force the propulsion assembly downwardly against the piston. A valve is operable when the piston is forced toward the one end of the cylinder to vent hydraulic fluid from the one end of the cylinder and an orifice is provided for controlling the flow rate of fluid through the valve to prevent the rapid descent of the propulsion assembly.