I have a yamaha ef2000is generator that is 6 months old. After about five minutes the generator sputters like it is going to shut off but then revs up again and continues to run with constant sputtering. It prodomitly does it on the economy mode. I think it is the carburetor like maybe the float bowl is getting stuck. I need help locating where the carburetor is the manual is of no use. I have checked everything else including oil levels, fuel filter ect. I have even changed the gas and made sure to have non ethanol fuel in it. Any suggestions?

Sounds like the carb is dirty. Try running the generator for a bit and when it sputters try slowly closing the choke to see if the generator will come out of its sputtering. If it does come out of it then you can start at the fuel tank and remove the filter screen in the tank and clean it well with an old toothbrush. If it is plugged with varnish it needs replaced. You can get by testing the unit by leaving it out and reassembling but you will need to replace it before actually using the generator. If the filter is clean check fuel lines for plugging and varnish along with the inline filter if it has one. If the lines and tank are clear you will need to pull the carb off, remove the bowl and clean the carb and jets. You may need to use a commercial carb cleaner if varnish is bad but be sure any plastic or rubber parts are removed before cleaning. Only immerse the entire carb if it is necessary. Try to remove the jets for cleaning. They can be a pain at times to remove but the jets and bowl are safe to immerse in carb cleaner. If the rubber o ring sticks to the bowl remove it before putting it in cleaner.

The reason choking the generator works when jets or fuel lines are plugged is because the choke blocks most outside are from entering the carb causing the engine to "****" harder through the jets in the carb.