In two words
ABSOLUTELY NOT
If you see 240 on the decal or see a 240 volt receptacle (anything other than 120 volts), it means you have Hatfield and McCoy 120 volt circuits. They can't get near each other without fireworks.
The problem with loading down one half of a generator's windings is that the motor labors and uses a lot more fuel, an unreasonable tradeoff. Why is this? The field for one, the rotor. The regulator senses that more rotor current is needed and sends more wattage to the rotor. Full fielding a rotor comes at a cost at the gas pump versus your wallet.
If you want to tap a serious amount of power, go online and purchase a 240 to 120 transformer. They are extremely efficient.