Carter B&B Updraft Carburetor Rebuild
- Remove screws which hold upper body and lower body.
- Lift off the upper body and pump assembly.
- Unscrew float hinge pin and lift out float and float needle.
- Remove main jet inlet valve, pump, check valve and economizer valve assembly
- Remove the main discharge nozzle.
- Remove vent tube.
- Remove step up piston plug, piston and spring.
- Remove idle passage tube.
- Soak parts overnight in a bucket of carburetor clean (any parts store brand)
- Wash with hot water to remove all chemicals.
- Blow out all passages with compressed air.
- Pay special attention to the step up rod parts. This must operate freely.
- Using thin wire clean out the ethanol residue left in the carburetor. Be careful not to enlarge the holes.
- Test the float by immersing in hot water. As the inside of the float heats up and expands, any hole will show up with bubbles.
Ready for your Carter B&B updraft carburetor kit.
- Reverse the disassembly instructions.
- The pin end of the economizer piston rod should be inserted in the economizer valve assembly.
A customer is working on a B&B updraft carburetor. We supplied a kit which does not have the 2 gaskets that go on the venturi. The parts are illustrated in the photo attached. #15 venturi gasket upper & #47 venturi gasket lower.
I’m not sure these gaskets are really needed anymore. What do you think?