Late Model YFA (aluminum base)
- Most YFA carburetors would have the star type of adjusting screw. This adjustment is important and should be performed anytime the carburetor is rebuilt, or the metering rod replaced.
- Remove the carburetor. We do not recommend working on your carburetor while on the car. This would chance dropping something into the engine.
- Back out the idle screw until the throttle plate is completely closed.
- Bottom the diaphragm by pressing down on the diaphragm shaft.
- The metering rod should contact the bottom of the well.
- For models with an adjusting screw, turn the screw until the metering rod bottoms in the well.
- Turn the screw one more turn.
- For models without an adjusting screw bend the lever the metering rod is attached to until the rod bottoms out.
This cutaway view should give you a better idea of what the metering rod system looks like. Disregard the TOOL as pictured. The tool has been out of production for many years. Use the instructions above.
Watch a video about adjusting the metering rod on a YFA type.