An outboard motor includes a cooling water passage including at least a portion disposed at a periphery of a catalyst and that guides cooling water that cools an exhaust passage, a vent hole disposed higher than the catalyst and that connects the interior of the cooling water passage to the exterior of the cooling water passage, and a restriction valve that allows a fluid to flow from the interior of the cooling water passage to the exterior of the cooling water passage via the vent hole and that restricts the flow of the fluid from the exterior of the cooling water passage to the interior of the cooling water passage via the vent hole.