Bob, if I never primed prior, my generator would require excessive cranking to start. So I don't know what more to say.
There is no hard fast rule for everyone because Onans seem to behave differently from one unit to another. I suppose it comes down to finding what works best for your PC.
I was taught that you should push the button to "stop" and hold it until the light comes on, then release it. Next push the button to start and it should start within a few seconds, maybe 10 seconds. Works every time for me. If you are holding the button on stop until the light goes out, you might be flooding it./quote]Ditto for me!
One item not covered... The transfer switch is in the wall in back of the drivers seat.