Appears to be a Briggs 030592 generator.
If so then It is more likely that either the voltage regulator [AVR] or rotor has failed. Disconnect the brushes note the wire connections. Using a 12v battery connect the positive terminal to the brush closest to end bearing and the negative to other brush. Now test for output if the rotor is okay you should find 120/240 range if not then the rotor failure is a good possibility. If you get 120/240 output range then it is likely it the AVR that has failed.