Water pump and engine

The embodiment of the utility model discloses a water pump and an engine. The water pump is applied to the engine, and comprises an impeller, a shaft connection bearing and a belt wheel, wherein the impeller and the belt wheel are installed on the shaft connection bearing in a pressing manner; the water pump also comprises a pump seat and a pump shell, wherein the pump shell is connected to the pump seat through a fastening bolt, the pump shell and the pump seat form a swirl chamber in an encircling manner, the impeller is positioned in the swirl chamber and the pump seat is used for being fixed on a cylinder body. According to the water pump provided by the embodiment of the utility model, the assembled water pump is directly installed on the cylinder body through the pump seat, so that the problem about the water pump does not need to be considered when the cylinder body is designing, and thereby casting and machining difficulty of the cylinder body are reduced.