The mechanical fuel pump has a diaphragm separating two chambers. Moving the diaphragm down draws fuel into the pumping chamber. A spring then moves the diaphragm up, forcing fuel from the pump, into the carburetor.
Most fuel tanks are in two parts joined by a weld around the flanges where the parts fit together. Baffles make the tank more rigid, prevent surging of fuel, and ensure fuel is available at the pickup tube.
