A snowmobile with arrangement of a four cycle engine is disclosed providing a relatively low center of gravity for improved handling and maneuverability. The engine comprises a cylinder unit slanted to the back of the snowmobile and an improved packaging of auxiliary components in order to optimize the location of the center of gravity on the snowmobile. The engine has a balancer shaft rotatably coupled to the crankshaft and the balancer shaft axis is positioned above the crankshaft axis.