Fuel supply assembly

A fuel supply assembly for a two-stroke crankcase scavenged combustion engine that is operated with layered scavenging, said assembly comprising:

• a housing and a first and second parallel channels extending through the housing, wherein the first channel is for a fuel/air mixture and the second channel is for auxiliary air;
• a partition wall extending in a plane between said first and second channels and arranged upstream and downstream of at least one butterfly valve, and the at least one butterfly valve having a butterfly pivotally mounted in the housing, said butterfly valve having an axis of rotation coinciding with the plane of the partition wall, having a downstream side, and an upstream side;
• and
• a protruding section which extends across the butterfly along the axis of rotation at least on the downstream side of the butterfly, wherein the housing includes fuel-conveying idling ducts that open in said first channel in the region of the butterfly valve, sealing member on the partition wall, substantially contacting said protruding section at least on the downstream side of the butterfly, thereby securing a seal between the two channels in all positions of the butterfly.