Abstract: An internal combustion with an arrangement for heating the suction gases in order to promote the vaporization of the fuel contained within the suction gases is disclosed. In the arrangement, the exhaust gases exhausted from the engine are routed around fins formed on the exterior wall of the bottom floor of the intake manifold for receiving the heat of the exhaust gases, and a covering is provided for enclosing the fins of the intake manifold in a closed chamber which is defined between the covering and the exterior wall of the intake manifold. The covering is provided with inlet and outlet ports so as to introduce the exhaust gases into the chamber and so as to drain the exhaust gases from the chamber. The introduced exhaust gases heat the entire surface of each fin so that the heat of the exhaust gases is transmitted to the fuel within the suction gases thereby accelerating vaporization of the fuel.