Stand-up type personal watercraft

1. A stand-up type personal watereraft comprising:

a body including a hull and a deck covering the hull from above, the body having a foot deck at a rear portion of the deck, on which an operator rides;

a water jet pump configured to propel the watercraft;

a four-cycle multi-cylinder engine provided within the body and configured to drive the water jet pump, wherein the engine is disposed forward of the foot deck within the body and substantially at a center position in a longitudinal direction of the body; and

a steering column that is pivotally supported on a front portion of the deck at a front end portion thereof and is configured to extend rearward in the longitudinal direction of the body;

wherein the foot deck is configured to extend from under a rear end portion of the steering column to a rear end portion of the body so as to include an axis located at a center in a lateral direction of the body so as to extend along the longitudinal direction of the body; and

wherein the four-cycle multi-cylinder engine is an inline four-cylinder engine and is mounted within the body to be located under the steering column such that a crankshaft thereof extends substantially in the longitudinal direction of the body and cylinders are oriented to extend substantially in a vertical direction of the body; and

wherein the engine includes a crankcase, a cylinder block located above the crankcase, a cylinder head located above the cylinder block, and an air-intake manifold and an exhaust manifold each connected to the cylinder head and extending downward from the cylinder head, through a position horizontally lateral of the cylinder block, to a position horizontally lateral of the crankcase.

2. The stand-up type personal watercraft according to claim 1 , further comprising:

an oil tank configured to reserve oil that circulates within the engine, wherein the oil tank is placed on an opposite side of the exhaust manifold relative to the engine and configured to extend upward from under the crankcase along a side wall portion of the crankcase and to have a space elongated in the vertical direction of the body at a position lateral of the crankcase.

3. The stand-up type personal watercraft according to claim 2 , further comprising:

an oil-collecting structure disposed at a rear portion of a bottom portion within the crankcase, and configured to collect the oil reserved in the crankcase of the engine and to deliver the oil to the oil tank.

4. A stand-up type personal watercraft comprising:

a body including a hull and a deck covering the hull from above, the body having a foot deck at a rear portion of the deck, on which an operator rides, the body being provided with a deck opening on an upper portion thereof;

a water jet pump configured to propel the watercraft; and

a four-cycle multi-cylinder engine provided within the body and configured to drive the water jet pump, wherein the engine is disposed forward of the foot deck within the body and substantially at a center position in a longitudinal direction of the body, and is constructed such that a cylinder head is located above a crankcase and a cylinder head cover provided over the cylinder head protrudes from an opening face of the deck opening toward outside of the body; and

a deck hood covering the deck opening, wherein the deck hood has a concave portion upwardly recessed and opposed to an upper portion of the cylinder head cover so as to accommodate the cylinder head cover therein, with the deck hood covering the deck opening, and an air flow space located laterally relative to the concave portion to allow air taken in from outside to flow therein.

5. The stand-up type personal watercraft according to claim 4 , wherein the air flow space forms a water separating chamber that serves to separate water from the air taken in from outside.

6. A stand-up type personal watercraft comprising:

a body including a hull and a deck covering the hull from above, the body having a foot deck at a rear portion of the deck, on which an operator rides;

a water jet pump configured to propel the watercraft; and

a four-cycle multi-cylinder engine provided within the body and configured to drive the water jet pump;

wherein the engine is disposed forward of the foot deck within the body and substantially at a center position in a longitudinal direction of the body;

a crankshaft contained within the crankcase of the engine;

a starter gear mounted on the crankshaft and configured to rotate integrally with the crankshaft by an output of a starter motor for starting the engine; and

an oil pump configured to deliver oil that circulates within the engine, the oil pump being provided with a pump gear for driving the oil pump, wherein the pump gear of the oil pump is configured to mesh with the starter gear.

7. A stand-up type personal watercraft comprising:

a body including a hull and a deck covering the hull from above, the body having a foot deck at a rear portion of the deck on which an operator rides;

a water jet pump configured to propel the watercraft;

a four-cycle multi-cylinder engine provided within the body and configured to drive the water jet pump, wherein the engine is disposed forward of the foot deck within the body and substantially at a center position in a longitudinal direction of the body;

a muffler provided in an exhaust passage of the engine;

an air cleaner box provided in an air-intake passage of the engine, wherein the muffler and the air cleaner box are arranged substantially forward and rearward relative to the engine; and

a steering column that is pivotally supported on a front portion of the deck at a front end portion thereof and is configured to extend rearward in the longitudinal direction of the body;

wherein the foot deck is configured to extend from under a rear end portion of the steering column to a rear end portion of the body so as to include an axis located at a center in a lateral direction of the body so as to extend along the longitudinal direction of the body; and

wherein the four-cycle multi-cylinder-engine is an inline four-cylinder engine, and is mounted within the body to be located under the steering column such that a crankshaft thereof extends substantially in the longitudinal direction of the body and cylinders are oriented to extend substantially in a vertical direction of the body.

8. A stand-up type personal watercraft comprising:

a body including a hull and a deck covering the hull from above, the body having a foot deck at a rear portion of the deck, on which an operator rides;

a water jet pump configured to propel the watercraft;

a four-cycle multi-cylinder engine provided within the body and configured to drive the water jet pump, wherein the engine is disposed forward of the foot deck within the body and substantially at a center position in a longitudinal direction of the body; and

two mufflers provided in an exhaust passage of the engine, wherein deck fins are provided at right and left side portions of the deck so as to protrude upward from an upper surface of the foot deck, and the mufflers are contained in the right and left deck fins, respectively.

9. The stand-up type personal watercraft according to claim 1 , wherein the air-intake manifold is spaced apart from the cylinder block at the position horizontally lateral of the cylinder block, and is spaced apart from the crankcase at the position horizontally lateral of the crankcase.

10. The stand-up type personal watercraft according to claim 1 , wherein the exhaust manifold is spaced apart from the cylinder block at the position horizontally lateral of the cylinder block, and is spaced apart from the crankcase at the position horizontally lateral of the crankcase.

11. The stand-up type personal watercraft according to claim 1 , wherein the air-intake manifold extends downward to a position horizontally lateral of a crankshaft positioned within the crankcase.

12. The stand-up type personal watercraft according to claim 1 , wherein the exhaust manifold extends downward to a position horizontally lateral of a crankshaft positioned within the crankcase.