Jason
If the smoke was an oil burning type smoke the place to look would be the PCV valve they are a reed type valve and can get gummed up on the Onan gas models because of condensation collecting in the crank case .
Also check the Genset engine oil level too much can cause PCV valve problems.
Next look at the air filter to see if there is any sign of oil in it or if it's plugged with dirt.
Hope this helps
Eric
