In at least some implementations, a charge forming device for a combustion engine includes a housing, a throttle valve and a vent valve. The housing has an inlet chamber in which a supply of fuel is received, a vent passage communicating with the inlet chamber and a throttle bore with an inlet through which air is received. The throttle valve is carried by the housing and has a valve head movable relative to the throttle bore to control fluid flow through the throttle bore. And the vent valve is electrically actuated, carried by the housing and has a valve element that is movable between an open position wherein fluid may flow from the inlet chamber through the vent passage and a closed position where fluid is prevented or inhibited from flowing out of the inlet chamber through the vent passage.