In at least some implementations, a charge forming device includes a main body having a throttle bore, a throttle valve, a housing and a circuit board including a throttle position sensor and a pressure sensor. The throttle valve is received at least partially within the valve bore, is rotatable between an idle position and a second position, and includes a magnet that is rotated when the throttle valve rotates. The housing is carried by the main body, and the circuit board is carried by the housing. A signal path is defined leading from the pressure sensor to a pressure source, the signal path includes a liquid collection area located below a gaseous area with respect to gravity.

An air flow velocity calculating device of a internal combustion engine, has a cylinder, a spark plug, an air intake passage, an air flow controlling valve, an air flow velocity calculating portion, and an electric discharge current controlling portion. An electric discharge between a center electrode and a ground electrode is sustained during an electric discharge sustaining period. The electric discharge sustaining period is a period from when the electric discharge begins to when the electric discharge is intercepted by the air flow. Energy is supplied to the spark plug, so that the electric discharge current is sustained at a constant value by the electric discharge current controlling portion during an ignition period. The ignition period is a sum of an electric discharge sustaining period of a first electric discharge and electric discharge sustaining periods of second and subsequent electric discharges in one cycle of the internal combustion engine.

A priming system for an engine system having a throttle valve configured to regulate a flow of air and fuel into an intake manifold of an engine is disclosed. The priming system may include a first sensor configured to generate a first sensor signal indicative of a value of an engine parameter, an auxiliary fuel line configured to direct fuel from a fuel source to a primed cylinder subset of the plurality of cylinders, an auxiliary fuel valve disposed in the auxiliary fuel line, and a controller in communication with the first sensor and the auxiliary fuel valve. The controller may be configured determine the value of the engine parameter from the first sensor signal and cease directing fuel from the auxiliary fuel line to the primed cylinder subset when the engine parameter value is greater than or equal to a threshold engine parameter value.

An engine fuel supply apparatus includes: a fuel chamber provided in a carburetor; a first communication passage for opening the interior of the fuel chamber to the atmosphere; a second communication passage for communicating the interior of the fuel chamber with the interior of a Venturi section; and a passage switching section capable of switching between the first and second communication passages and mechanically connected to the main switch so that it can operate in response to the main switch shifting between an ignition position and a stop position. The passage switching section switches the second communication passage to the first communication passage in response to the main switch shifting from the stop position to the ignition position and switches the first communication passage to the second communication passage in response to the main switch shifting from the ignition position to the stop position.

A fuel delivery arrangement for a generator can include a throttle-mixing assembly including a mixer body defining a main port extending between an air inlet end and a mixed air-fuel outlet end and defining a fuel inlet port extending into the main port, a Venturi structure located within the main port and being configured to mix fuel received from the fuel inlet port with air received from the air inlet end and to deliver an air-fuel mixture to the air-fuel outlet, a fuel control valve assembly, mounted to the mixer body, including a first valve and a first actuator arranged to control a flow of the fuel passing through the fuel inlet port, and a throttle control valve assembly, mounted to the mixer body, including a second valve and a second actuator arranged to control a flow of the air-fuel mixture passing through the main port.