Float bowl style carburetors require float bowl venting to work properly, just ask anyone who has ever had plugged or frozen vent lines. The Lectron® carburetor, like other more conventional carbs, vents its float bowl through external vent/overflow hoses that hang down in front of the rear wheel. The SmartCarb® vents its float bowl quite differently – from inside the airbox via a scoop/port located in the top of the venturi bell.
This patented internal venting feature allows the SmartCarb® to compensate for a wider range of air densities compared to other carburetors. Recent testing proves air/fuel mixture consistency up to a simulated 22,000 feet on drone engine applications, for example.
Venting and airflow communication between the airbox and the float bowl applies a steady, equalized pressure against the fuel in the bowl that is proportional to air density and also velocity inside of the airbox. Put simply, more dense, heavier air drives more fuel flow, less dense air drives less fuel flow, and air/fuel ratios stay consistent regardless of elevation or temperature changes.
Beyond improved air density compensation, internal float bowl venting also provides for sufficient top end fueling in the SmartCarb® without the need for a power jet. Although the original Lectron® carburetor of 1974 did not have a power jet, all modern iterations of the design come with at least one or more power jets to provide additional fuel to the mix from mid to top.