Tom, when we had our Mountain Aire Diesel, Newmar said we could only run our 7.5 22 hours at a time and had to shut down for 2 hours a day min. They said no running 4 hours a day would be better for it. But that was Newmar, not Onan. I was really apprehensive to run mine for 5 days straight!
Dave , I did some oilfield work where we ran generator basically 24/7.(not coach generator, genset on location to power our equipment) We did however shut it down +/-5 minutes a day to check oil level. Also change oil & filters every 250 +/- hrs. I try to do same on coach usually go out & check oil after or with morning coffee. It has never needed to have any added, but I feel better knowing for sure it was OK in the morning.
Newell has a history of building coaches for racing teams who run their generators non-stop for days at a time. Stopping them daily to check the oil is a good idea and changing the oil and filters every 150-250 hours (500 hours if you are running synthetic) is a good idea.
If my engine is on and it is over 60 degrees outside, you can bet that my generator is running. I don't dry camp often but when I do, my generator is running all of the generator-allowed hours.
As my wife says, 'I have an RV so I don't have to camp.'
my generator has over 8000 hours on it. still running good
tom