<p>The invention provides a pump for pumping a liquid, in particular for pumping fuel oil in a burner. The pump comprises a rotor (6) positioned in a chamber (3) of a housing (2) . The rotor rotates relative to the walls (4; 5) of the housing, and to prevent contact between the rotor and the walls, the pump comprises a retaining structure (15) with an axial bearing (19) . The bearing comprises one bearing component (20) which rotates with the shaft (7) and one bearing component (21) which is fixed relative to the housing. The bearing is located in a first spacing between an enlarged section (23) of the shaft and an outer surface (24) of the housing.</p>
