Thanks everyone but yes as Bill pointed out, this has nothing to do with exhaust fumes. Thats not a problem as the exhaust vents out and away from any open doors or windows.
The thread is about the hot air the generator engine creates while cooling itself. The inlet for cool air to cool the air cooled gen is potentially sucking in the hot air coming out directly next to it. That constant recirculation of hot air re-entering the cool air inlet has to warm the generator more than if it was only pulling fresh cool air away from that exiting hot air. It would be like the air coming out of your trucks radiator coming around the front and re-passing through the radiator again. That clearly wouldn't be good for dissipating more radiator heat would it?
And no, you cant run the gen with the cover off otherwise the air cooling fan cant pull air over the engine, but again this isnt the topic. Maybe I can post a picture if I get a moment.
