Abstract: A pump (60, 160) has a pair of working members (preferably diaphragms 1, 2, 101, 102) and a pump chamber (3, 4, 103, 104) associated with each working member is communicated via check valves (32-35, 132-135) to a suction manifold (30, 130) and to an outlet manifold (31, 131). A drive mechanism (10, 110) couples the working members so that they reciprocate together and a first of the working members performs an outlet stroke while a second of the working members performs a suction stroke. The suction and outlet manifolds (30, 130, 31, 131) are incorporated in a manifold assembly that connects the pair of diaphragms (1, 2, 101, 102) for coordinated reciprocation. A pair of manually-operated levers (J, 8, 107, 108) are connected together for opposite reciprocation and are drivingly connected to the working members (1, 2, 101, 102).