Champion Generator not even close to rated output

you have a fuel issue, generator's should never stall period, they should either throw a breaker or drop down to a very low voltage the motor can spin.

it actually sounds like a supply issue. make sure when you clean the carb, you clean the fuel inlet from the gas tank to the valve seat on the float, i see alot of issues there. sounds like the fuel bowl is running dry

and yes, use carb cleaner, not ether.