Do you have the manual for the generator? It gives steps to diagnose low/no output. It also has wiring diagrams that show what all that stuff is. On quick inspection, I'd guess those wires were added for an external voltage meter. They appear to have non-factory crimped connectors where they attach inside the unit, and appear to be connected to the main AC output terminals. But I can't be sure without knowing your exact model number which looking back through this thread, you never determined.
One thing I see in the schematics is a switch - looks like a toggle switch - that selects between voltage regulation using the transformer, and regulation using an electronic AVR (Automatic Voltage Regulator). If you have no AVR and that switch is set to "ELEC", then I think you will get no output. Check to be sure it's set to "COMP" to use the transformer.