Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Locate the choke flap in the carburetor and see if it is staying wide open when engine is running, if not, see if spring is missing or broke,that keeps it open when not being used for start. You can always use a spring or wire to hold the choke flap open.
only other thing would be the needle valve and float in the carburetor, not controlling the fuel flow into the float bowl, where the gas is sucked into the engine. Needle valve may not be seating, or the float may be stuck or is filled with gas!
I may have been a bit hasty, I thought you had said it was black smoking, showing to be flooding.. That was another question I was dealing with. Is the load close to the max. or not. The higher the wattage usage, the more fulel it will require.
All you can do is check he choke, and the needle valve and float. You may have carburetor with wrong jet for your altitude it has high altitude jet and you are close to sea level, the fuel consumed would be more because of the air to fuel mixture.
It is for idle mix adjustment, nothing else on the carb is adjustable, other than the external throttle adjustment. There is no service manual on the generator that I have ever seen.