While the Zoeller pumps are one of the better pumps out there, they are not very efficient. The M53 runs at 9.6 amps and requires 25.9 amps to start. When using the formula of amps X volts = watts, you would need a minimum 1152 running watts and 3108 starting watts to operate your pump. When using generators, you should never load them up any more that 80% of their capacity at any time, so you might consider a generator with about a 4000 watt starting watt capacity.