237-600 Tillotson Main Metering Diaphragm operates to open the fuel inlet needle valve, allowing fuel to flow to the high and low fuel circuits.
You may hear us describing this diaphragm as the one with the metal "wagon wheel" in the middle. The "wagon wheel" stabilizes the diaphragm and helps to control its movement, so the dimple in the center is right above the tip of the fulcrum arm.
We recommend replacing this diaphragm every 3-5 races, or if you see a worsening change in performance, whichever happens first.
237-600 Tillotson Main Metering Diaphragm fits all HL, HR, HW, HX, HM Model Carburetors including HL-1A HL-129E,HL-132H,HL-166B&C,HL-189F,HL-227A,E,HL-229A,HL-321E,HL-232A,E, HL-250A,B,C,D,E HL-274E,HL-,292G,HL-293A,F,HL-299E,HL-304E, HL-304WX,WXA,WXG,HL-306A, HL-314E,HL-314F&G, HL-324A,HL-334A,AA,B,AB,WX,WXA,WXG,HL-339A,HL-341A,HL-342A,HL-348A,B,C,D,E, HL-352A,HL-355A,B,C,D,E HL-357A,B, HL-360A, HL-360B,C HL-365A&B,HL-366A,HL-368A,HL-371A,HL-374A, HL-380A,B,HL-383A,HL-384A&B, HL-385A, HL-388A,HL-395A,HR-181B,HR-184A,HR190A,HR-191C,HR-191G,HR-196A, HW-10A,B HW-11A,B HW-22A, HW-23A, HW-27A, HW-30A, HW-31A, HW-32A, HW-33A, HW-34A, HW-35A, HW-43A, HB-10A, HB-11A, HB-12A, HC-102A, HC-103A,HC-112A, HM-1A, HM-2A, HM-12A, HX-10A, HX-12A
This is not the same main metering diaphragm used on HD model Tillotson carburetors.