with a passage 54 in the body 12 and eventually to passage 14 at a location upstream of throttle blade 16 in the manner to be described in the next paragraph the upper air inlet end of housing 12 supports a generally cylindrical member 56 having end portion 56 39 telescopically extending into the upper end portion of the housing 12 likewise a second member 58 is supported by member 56 member 58 includes an open inlet end 60 communicated wtih an internal passage defined by inner wall means 62 which projects radially inward from end 60 to a lesser diameter mid wall means 64 thereafter wall means 66 projects radially outward to merge with an inner cylindrical wall 68 of member 56 member 58 defines two axially extending channels 70 and 72 as shown in fig1 and 2 the channels 70 and 72 terminate in axial facing shoulder portions 74 and 76 respectively the channels receive edge portions 78 and 80 of a venturi assembly 82 specifically the edge portions 78 and 80 are formed on the outer ends of radially directed struts 84 and 86 from a cylindrical mid portion 88 of the venturi assembly 82 the struts 84 and 86 are relatively thin to permit the flow of air thereby.