The KidWind video on the KidWind Small Water Pump with Tubing (KW-PUMP) reports the minimum voltage as 1.7 volts and 50 mA. We have operated the pump at up to 5 volts.

The specifications sheet from the manufacturer lists:

Rated voltage: 3.0 V/DC
Rated current: 80 mA
Water delivery height: 40 cm
Water delivery capacity: 0.05 CBM/hour
Water pump connecting with 15 cm Alligator Clips

Pump motor portion: length 44 mm, diameter 23 mm
Height of pump outlet 31 mm.
Outside diameter of outlet: 7 mm
Flow rate: ~12 mL/second at 3 V and ~25 mL/second at 5 V

Which generator should I use to pump water?
What are the specs for the generator(s) in the KidWind kit?