Duplex aspiration system

The Duplex aspiration system fitted to chain saw models PS-340 to PS-411 guarantees smooth, reliable running throughout the speed range – from idling speed to full revs when cutting. The separate intake channel for the idling mixture runs parallel to the main aspiration path and enters the cylinder below the inlet port. As the Duplex aspiration channel is opened by the piston before the main inlet port, a vacuum is created when the throttle shutter remains closed. A collecting groove in the flange is positioned symmetrically to the idling jet of the carburettor and collects the fuel which is needed to keep the engine idling. The small cross-section of the Duplex aspiration channel generates a high-speed flow. This prevents unwanted droplets of fuel from being deposited on the wall of the channel and thus ensures an optimum air-fuel mixture