A valve (1,1) for a marine propulsion unit comprises a body (2) having an internal passage (3) through the valve body (2). An aperture (5) in the valve body communicates with the internal passage (3). A piston (4,4) is moveably mounted within the internal passage. The valve is configured such that, upon immersion or expected immersion of part (such as an air intake) of an associated propulsion unit in water or tilting of the associated propulsion unit beyond a predefined angle, the piston moves to a first position within the internal passage in which it seals the aperture. If for example the air intake of a marine propulsion unit of a vessel is connected to the aperture (3), the effect of the piston sealing the aperture (5) is to isolate the air intake from the atmosphere. Thus if the vessel sinks or capsizes, the valve closes the air intake of the propulsion unit and so prevents entry of water into the propulsion unit.

An exhaust gas recirculation system is provided for an internal combustion engine having reciprocating piston design with an exhaust gas turbocharger unit having an exhaust gas turbine and a supercharger. The internal combustion engine has a machine housing accommodating one or more cylinders having reciprocating pistons, which is provided with a suction unit and an exhaust gas outlet unit, which is connected to the exhaust gas turbine by way of an exhaust gas line. The exhaust gas line supplies at least a part of the exhaust gas stream to the suction unit via the exhaust gas recirculation system. To optimize the exhaust gas recirculation system, it has a pipe branch, which is connected to the exhaust gas line and is connected to an exhaust gas recirculation line with a control element interconnected. The exhaust gas recirculation line extends, on the one hand, with a first supply line section outside and, on the other hand, with a second supply line section in an interior of, a suction unit container of the suction unit. An exhaust gas stream is conveyed by the second supply line section into the suction unit container for targeted mixing of exhaust gases with the air volume contained in the suction unit container.

The present invention is a system for air supply to the engine of a motor float comprising a bottom part and an upper part of the body defining the inner space of the float, in which a combustion engine is arranged, wherein the upper part of the body is in its front part provided with an air supply, characterized in that the combustion engine is arranged in the engine compartment and separated from the rest of the inner space of the float by means of a partition provided with a suction opening in its front part, wherein to provide the circulation of air in the inner space of the float a sealing rib extends from the front part of the partition towards the tip of the float, separating the air supply and suction opening from one another, wherein at least one rear pump for sucking the leaking water is arranged in the rear part of the inner space of the float. The main object of the invention is thus to use the interspace of the float to provide separation of water and air, when eventual separated water may be sucked away by a pump operating on any principle (electric, vacuum, etc.).

A watercraft propulsion unit includes an engine body, a throttle body, an intake passage, and a resonator. The throttle body is configured to supply air to the engine body. The intake passage is connected to the throttle body on an upstream side of the throttle body. The intake passage includes an intake inlet to draw in the air and an intake outlet to guide the air to the throttle body. The resonator is connected to the intake passage to reduce an intake sound of the air. A volume of an internal space of the resonator is greater than a volume of an internal space of the intake passage between the intake inlet and the intake outlet.