Watercraft propelled by a water jet

A watercraft propelled by a water jet comprising:

• a hull including an upper deck and a bottom surface defining a space therebetween, the hull including a sealed hull portion;
• an engine compartment located adjacent the sealed hull portion and containing a propulsion and steering system including an engine, a bladed impeller driven by the engine for inducting water and forcing the inducted water away from the craft through a directionally displaceable nozzle;
• a control lever located on the upper deck including a steering control for adjusting the directional displacement of the nozzle;
• a cowling for covering and sealing an opening formed in the upper deck, the opening providing access to the engine compartment, the cowling including an air inlet defining a duct in which air is carried to the engine compartment and including
• a frame defining an opening to the duct and a valve seat about the opening, and
• a valve that moves away from the valve seat to a first position, at which the duct is open, and into engagement with the vale seat at a second position, at which the duct is closed
• wherein gravity urges the valve to the first position when the watercraft is upright and to the second position when the craft is inverted and wherein the valve is made from a material lighter than water such that the valve is urged to the second position against the force of gravity when the craft is upright and submerged in water.