Air-intake system for watercraft

A small watercraft is comprised of a hull having a longitudinal axis and an engine compartment containing an engine, the engine including a plurality of cylinders and an output shaft arranged to lie generally parallel to the longitudinal axis, a flywheel carried by the output shaft on a rear side of the engine and generally covered by a flywheel casing, an impeller shaft coupled to the output shaft, an air intake system connected to the engine and communicating with each cylinder of the engine through intake passages in the engine, and an exhaust system connected to the engine and communicating with each cylinder of the engine through exhaust passages in the engine, said exhaust system extending from the engine exhaust passages to a discharge end that opens outside of the engine compartment, the exhaust system including a water lock located at least in part behind the engine with at least a portion of the flywheel casing being arranged between at least a portion of the water lock and at least a portion of the air intake system, the air intake system including a downwardly-facing opening that communicates with an intake air silencer, the air intake system further including a plurality of intake pipes that lie between the intake air silencer and the intake passages of the engine, the intake pipes being bent downward toward the intake air silencer.

A small watercraft is comprised of a hull having a longitudinal axis and an engine compartment containing an engine, the engine including a plurality of cylinders and an output shaft arranged to lie generally parallel to the longitudinal axis, a flywheel carried by the output shaft on a rear side of the engine and generally covered by a flywheel casing, an impeller shaft coupled to the output shaft, an air intake system connected to one side of the engine and communicating with each cylinder of the engine through intake passages in the engine, and an exhaust system connected to the engine and communicating with each cylinder of the engine through exhaust passages in the engine, said exhaust system extending from the engine exhaust passages to a discharge end that opens outside of the engine compartment, the exhaust system including a water lock located at least in part behind the engine with at least a portion of the flywheel casing being arranged between at least a portion of the water lock and at least a portion of the air intake system, the air intake system including a downwardly-facing opening that communicates with an intake air silencer, the air intake system additionally including an intake air box into which the air flows from the downwardly-facing opening, and from which air flows into the intake air silencer.

A small watercraft is comprised of a hull having a longitudinal axis and an engine compartment containing an engine, the engine including a plurality of cylinders and an output shaft arranged to lie generally parallel to the longitudinal axis, a flywheel carried by the output shaft on a rear side of the engine and generally covered by a flywheel casing, an impeller shaft coupled to the output shaft, an air intake system connected to the engine and communicating with each cylinder of the engine through intake passages in the engine, an exhaust system connected to the engine and communicating with each cylinder of the engine through exhaust passages in the engine, said exhaust system extending from the engine exhaust passages to a discharge end that opens outside of the engine compartment, the exhaust system including a water lock located at least in part behind the engine with at least a portion of the flywheel casing being arranged between at least a portion the water lock and at least a portion of the air intake system, and an air duct to guide ambient air into the engine compartment of the watercraft, the air duct having an opening located below an intake opening of the intake air system.

A small watercraft is comprised of a hull having a longitudinal axis and an engine compartment containing an engine, the engine including a plurality of cylinders and an output shaft arranged to lie generally parallel to the longitudinal axis, a flywheel carried by the output shaft on a rear side of the engine and generally covered by a flywheel casing, an impeller shaft coupled to the output shaft, an air intake system connected to the engine and communicating with each cylinder of the engine through intake passages in the engine, an exhaust system connected to the engine and communicating with each cylinder of the engine through exhaust passages in the engine, the exhaust system extending from the engine exhaust passages to a discharge end that opens outside of the engine compartment, said exhaust system including a water lock located at least in part behind the engine with at least a portion of the flywheel casing being arranged between at least a portion of the water lock and at least a portion of the air intake system, and an air duct which extends into the engine compartment to introduce ambient air into the engine compartment, the air duct including a lower opening which is positioned next to an air inlet opening of the intake air system.

A small watercraft is comprised of a hull having a longitudinal axis and an engine compartment containing an engine, the engine including a plurality of cylinders and an output shaft arranged to lie generally parallel to the longitudinal axis, a flywheel carried by the output shaft on a rear side of the engine and generally covered by a flywheel casing, an impeller shaft coupled to the output shaft, an air intake system connected to the engine and communicating with each cylinder of the engine through intake passages in the engine, and an exhaust system connected to the engine and communicating with each cylinder of the engine through exhaust passages in the engine, the exhaust system extending from the engine exhaust passages to a discharge end that opens outside of the engine compartment, the exhaust system including a water lock located at least in part behind the engine with at least a portion of the flywheel casing being arranged between at least a portion of the water lock and at least a portion of the air intake system, the air intake system including a plurality of intake pipes that extend between an intake air silencer and the intake passages of the engine, the intake pipes being bent downward toward the intake air silencer.

A small watercraft comprised of a hull defining an engine compartment between fore and aft ends of the hull, an internal combustion engine positioned within the engine compartment, the engine including at least one combustion chamber, at least one intake passage which selectively communicates with the at least one combustion chamber, at least one exhaust passage which selectively communicates with the at least one combustion chamber, and a plurality of valves that regulate fluid flow through the intake and exhaust passages, and an induction system connected to an influent end of the intake passage, the induction system being arranged within the engine compartment such that an inlet to the induction system is positioned lower than the influent end of the intake passage of the engine.

A small watercraft comprising a hull defining an engine compartment, a four-cycle internal combustion engine positioned within the engine compartment, the engine including at least one combustion chamber, at least one intake passage which selectively communicates with the combustion chamber, and an induction system connected to an intake port on the engine that communicates with the intake passage, the induction system including at least one intake pipe that is bent downward toward an intake silencer and communicates with a plenum chamber within the intake silencer, the intake silencer including an inlet opening and a drain hole, the drain hole being provided on a lower portion of the intake silencer, the inlet opening being arranged on the intake silencer at a position higher than the drain hole.