Personal watercraft

A personal watercraft comprising:

• a water jet pump;
• a cooling water passage of an engine;
• a first water passage from the water jet pump to the cooling water passage, wherein a filter for the cooling water is provided in the first water passage;
• a second water passage opened in a surface of a body of the watercraft and communicating with the first water passage, the second water passage branching from a position of the first water passage between the filter and an inlet of the cooling water passage;
• and
• an opening/closing means for opening/closing the second water passage ,wherein
• a cooling water is forcibly sent by the water jet pump and led to the cooling water passage through the first water passage, and
• the water flows through the cooling water passage while exchanging heat, and the resulting water is discharged outside the body of the watercraft.

A personal watercraft comprising:

• a water jet pump;
• a cooling water passage of an engine;
• a first water passage from the water jet pump to the cooling water passage;
• a second water passage opened in a surface of a body of the watercraft and communicating with the first water passage;
• and
• an opening/closing means for opening/closing the second water passage, wherein
• a cooling water is forcibly sent by the water jet pump and led to the cooling water passage through the first water passage,
• the water flows through the cooling water passage while exchanging heat, and the resulting water is discharged outside the body of the watercraft, said personal watercraft further comprising:
• an expansion chamber in an exhaust system of an engine;
• and
• a water muffler provided at a position downstream of the expansion chamber in the exhaust system of the engine, wherein
• the expansion chamber has a double-walled structure comprised of inner and outer walls between which water flows and is provided with a water-supply hole in the inner wall to allow water to be supplied into inside of the expansion chamber through the water-supply hole,
• an inspection hole is formed in the outer wall at a position corresponding to a position of the water-supply hole, and
• a cap member is removably attached to the inspection hole.

A personal watercraft comprising:

• an expansion chamber in an exhaust system of an engine;
• and
• a water muffler provided at a position downstream of the expansion chamber in the exhaust system of the engine, wherein
• the expansion chamber has a double-walled structure comprised of inner and outer walls between which water flows and is provided with a water-supply hole in the inner wall to allow water to be supplied into inside of the expansion chamber through the water-supply hole,
• an inspection hole is formed in the outer wall at a position corresponding to a position of the water-supply hole, and
• a cap member is removably attached to the inspection hole.