Various embodiments of the teachings herein include a mixer disposed in a fuel gas combustion system and mixing air and fuel gas to form flammable mixed gases. The mixer may include: a Venturi tube having an air inlet, a fuel gas inlet, a gas mixture outlet, a central axis direction, and a throat positioned between the air inlet and the gas mixture outlet in the central axis direction, wherein the fuel gas inlet is disposed at the throat; and an adjustment component disposed in the Venturi tube downstream of the throat, the adjustment component drivable to move towards or away from the throat in the central axis direction, thereby changing a flow area of gas in the Venturi tube. The adjustment component comprises a conical valve plug with a conical outer surface thereof at a side facing towards the throat and fitting an inner surface of the Venturi tube.

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.

A power machine can include a frame, an engine supported by the frame, and an air intake system that directs intake air to the engine. The air intake system can include a filter assembly that includes a filter housing and a filter element positioned in the filter housing to filter contaminants from the intake air. A pressure source can be arranged to pressurize filtered air from the filter assembly and provide the pressurized filtered air to an intake of the engine. The air intake system can further include an ejector arranged to receive a portion of the pressurized filtered air and induce a suction flow at the filter housing to eject contaminants from the air intake system.