Patent ID: 6941925

Claim:
A fuel supply control system for an engine, comprising a diaphragm attached to a valve housing to define a negative pressure working chamber, a control valve which is connected to the diaphragm and which is operable to be opened and closed by advancing and returning of the diaphragm due to generation and extinction of a negative pressure in the negative pressure working chamber, the control valve being incorporated into a fuel passage system which provides communication between a portion of a fuel tank below a fuel oil surface and a fuel supply section in the engine, the negative pressure working chamber being in communication with a negative pressure generating section in the engine through a negative pressure conduit, wherein an oil flow-out preventing means is provided in a connecting portion for connecting the negative pressure generating section and the negative pressure conduit to each other, the oil flow-out preventing means being adapted to provide communication between the negative pressure generating section and the negative pressure conduit in an operational attitude of the engine, but to cut off the communication between the negative pressure generating section and the negative pressure conduit by a lubricating oil received from the negative pressure generating section, when the engine is inclined at a given angle or more.