I haven't exercised our generator in 2 months and now it seems to surge. That is, the lights seem to get brighter then dimmer about once every 5 minutes. It is enough that you notice it. It starts and runs smooth. The only issue is the fluctuating of the unit that makes the lights go brighter & dimmer inside the coach. We ran it for 2 hrs. today and put a load on it using our electric heater. Do you think this will correct itself if I just use it every day for awhile? Or, is there some other maintenance needed to fix what seems to be fluctuating power? Thank you for any info.