Fuel feed system of engine

A fuel feed system of an engine comprising:

• an engine case;
• a fuel tank fixed above the engine case;
• an auto fuel cock arranged between the engine case and the fuel tank and fixed to a lower surface of the fuel tank;
• and
• a negative pressure tube, wherein the inside of the engine case is connected to the auto fuel cock via the negative pressure tube,
• wherein the auto fuel cock includes a first negative pressure introduction joint projected downward,
• the engine case includes a second negative pressure introduction joint projecting upward from an upper surface of the engine case,
• the negative pressure tube includes a first connection part fitted onto the first negative pressure introduction joint and a second connection part fitted onto the second negative pressure introduction joint, and
• the negative pressure tube is positioned so that the first connection part of the negative pressure tube, of which the second connection part is fitted onto the second negative pressure introduction joint, is located on a movement passage of the first negative pressure introduction joint of the auto fuel cock, when the fuel tank to which the auto fuel cock is fitted is moved downward to be fixed above the engine case.