Water cooled engine

The invention provides a water cooled engine capable of suppressing the thermal deformation of a cylinder head. A head water jacket (20) includes an inter-exhaust-port-wall water channel (29) betweena first exhaust entrance port wall (3d) and a second exhaust entrance port wall (3e). A cylinder head (6) includes a cooling water injection passage (27) provided at a bottom wall (6c) of the cylinderhead (6). The cooling water injection passage (27) is positioned on the exhaust end (6a) side, and includes a passage entrance (27a) provided on the exhaust end (6a) side, and a passage exit (27b) directed toward the inter-exhaust-port-wall water channel (29). An exhaust port wall includes a heat dissipation fin (28) extending from a first exhaust entrance port wall (3d) toward an exhaust end (6a). The space between the heat dissipation fin (28) and a second exhaust entrance port wall (3e) forms a water channel entrance of the inter-exhaust-port-wall water channel (29). 本发明提供能够抑制气缸盖的热变形的水冷发动机。盖水套(20)在第排气入口端口壁(3d)与第二排气