A pair of items in a carburetor . The seat is usually a brass plug with a specially shaped hole to accommodate the needle which is a shaft with a pointed end. When the needle is fully seated in the seat, no gasoline can enter the float bowl . As the needle is lifted off the seat some gas pours into the float bowl . The needle moves when the float in the float bowl drops below a set height.
NEEDLE AND SEAT
Meaning of NEEDLE AND SEAT in English
English dictionary of automotive terms. Английский словарь автомобильных терминов. 2012