A carburetor includes a carburetor bowl, a fuel supply pipe, a fuel drain pipe, and a valve. The carburetor bowl is configured to store fuel and provide the fuel to an air passage. The fuel supply pipe is connected a fuel tank and the carburetor bowl. The fuel drain pipe is connected to the carburetor bowl and the fuel supply line. The valve for the fuel drain pipe is configured to open and close in response to an orientation of the carburetor.

A manually actuated feed pump is provided with a primer bulb to be manually actuated by an operator. The primer bulb has a pump chamber. A travel-controlled valve connects the pump chamber to a fuel line. The travel-controlled valve has a valve member that is moved by an actuation travel of the primer bulb into an open position that opens the travel-controlled valve. A first spring is operatively connected to the valve member and to the primer bulb. The primer bulb acts through the first spring on the valve member.

A diaphragm pump includes a discharge chamber, a diaphragm configured to be actuated by a pulsation pressure, a fuel flow path fluidly coupled with the discharge chamber, and a fuel chamber located on the fuel flow path. The diaphragm includes a diaphragm actuating portion forming a part of the discharge chamber, and configured to suction fuel into the discharge chamber and to discharge the fuel from the discharge chamber in response to being actuated by the pulsation pressure, and a valve actuating portion located in the fuel chamber and configured to selectively open and close the fuel flow path.

In at least some implementations, a carburetor has a metering system that controls fuel flow from a fuel source to an air-fuel passage. The metering system includes a metering diaphragm sealed to a body of the carburetor to at least partly define a metering chamber between the metering diaphragm and the body, and the metering diaphragm has a continuous layer and a discontinuous layer. The continuous layer is responsive to fluid pressure within the metering chamber and moves against the discontinuous layer to open a metering valve to allow fuel flow from the fuel source and into the metering chamber when said fluid pressure is below a reference pressure.