Abstract: Engine starting device which, if engine temperature is at a level such that vaporized fuel may be present in a carburetor while an engine is stopped, causes a throttle valve to open a certain amount when the cranking motor is actuated, whereby such vaporized fuel is rapidly evacuated and an air-fuel mixture having the correct air-fuel ratio to permit rapid starting is supplied to the engine.

Abstract: Rotary piston engine having a first intake port formed in rotor housing and one or more second intake ports formed either one or both of the rotor and side housings. The first intake port supplies relatively rich air-fuel mixture having mixing ratio of 2 to 6 and the second intake port supplies air or relatively lean mixture in such a manner that the total air-fuel ratio becomes 15 to 20.

Abstract: A control system for controlling an air-fuel mixture to a preferable ratio required in an internal combustion engine during any of the engine operating conditions, which preferable ratio is variable in response to the engine operating condition. In one embodiment, the control system is arranged to regulate the amount of fuel, to be jetted into the intake passage leading to at least one combustion chamber of the engine through a main discharge nozzle, in response to the pressure of fuel vapor inside a fuel tank. In another embodiment, the control system is arranged to regulate the amount of fuel, to be jetted into the intake passage through one or both of the low speed port and the idle port, in response to the pressure of fuel vapor inside the fuel tank. The control system is usable in association with an internal combustion engine of any type having a fuel evaporation control system.