Abstract: Disclosed is a jet-propulsion watercraft capable of maintaining cooling capability in an exhaust passage even when one cooling water passage is clogged with substances. The jet-propulsion watercraft comprises: an engine having a cooling water passage; an exhaust passage having a double-walled structure comprised of inner and outer walls between which a cooling water passage is at least partially formed; a water jet pump, the water jet pump pressurizing and accelerating water and ejecting the water from the outlet port, and supplying part of the water to the cooling water passages of the engine and the exhaust passage; a water-supply hole formed in the inner wall of the double-walled structure; a first cooling water passage for supplying the cooling water to the cooling water passage between the outer wall and the inner wall; and a bypass passage formed independently of the first cooling water passage.

Abstract: A holding structure for holding a device on a fuel tank can be manufactured by small man-hours, and is simple in construction and excellent in vibration isolating performance. The holding structure holds a device (11) inserted in a fuel tank (10) on the fuel tank (10). The holding structure includes a holding tube (19) formed integrally with the fuel tank (10) so as to surround an opening (18) formed in the fuel tank (10), an elastic boot (21) put on the holding tube (19) so as to be in close contact with the outer circumference (19a) of the holding tube (19) and the outer circumference (15a) of a part of the device (11), extending outside from the holding tube (19), and a fastening device (22, 23) for fastening the elastic boot (21) to the respective outer circumferences (19a, 15a) of the holding tube (19) and the device (11).

Abstract: A reed valve for opening and closing an intake passage of an engine includes a valve body having a valve hole and a valve seat, and a reed piece made of a resin. The reed piece has a base end of which is supported by the valve body so as to be seated on a valve seat surface of the valve seat. An elongated member is formed on the valve body so as to extend across the valve hole. The outer surface of the elongated member lies in a plane including the valve seat surface. According to the present invention having the above described structure, bending deformation of the reed piece at the closed state can be deterred.