To lessen a load applied to an engine for drawing in a mixture and to reduce concentration of air supplied to a combustion chamber of the engine.

An engine control mechanism uses an air conditioner 52 for conditioning air in a cabin and an engine mechanism provided with a plurality of cylinders, each being provided with at least a pair of an intake valve and an exhaust valve, an inlet portion for drawing the mixture into the combustion chamber in the cylinder by way of an intake valve, an exhaust portion for exhausting a combustion gas from the combustion chamber in the cylinder by way of the exhaust valve, and a valve mechanism for driving to open or close the intake and exhaust valves. The control mechanism is capable of sending air to be sent from the air conditioner 52 into the cabin to a carburetor by way of a duct 51.