Onan microlite 2800

I had the exact same issues with mine after it sat unattended for some time. This is how I solved my issue which I am sure some will say is wrong. First is I used surefire (ether based) type product sprayed down the throat of the carburetor while trying to start it. The ether gave it a quick boost and the genrator startted right up, although ran very poorly......I let it run under as much load as it would take for an hour with out it dying. I then (While it was running) sprayed Seafoam Spray Cleaner and Lube down the carburetor effectively choking the generator to a stop. I let it sit for a few hours and then Tried restarting it. It wouldn't go so I used some ether and off it went (you'll see alot of white smoke coming out the exhaust so don't be alarmed its normal). the Generator ran better and better as I let it run under load. I now make sure to start the Generator once a month and run it under load. good luck