I have a Amico electrical generator that doesn’t put out any juice. What do I need to check & in what order?

This is a gas generator about 3 years old. The motor works fine but no electricity output.The wires are all connected properly with no burned ones. HELP !
The genset is an Amico 3300 watt with a WG200 motor (6.5HP and 200cc) OHV gas motor. The breakers are on (110 and 220) but the voltmeter shows no juice and there is no current at the receptacle plugs.
The motor works fine and the generator is turning. My guess is that there is an electrical problem and I need to know what wires do I check in what order.