Agreed.

On a honda eu 3000, the maintainance schedule calls for oil changes every 100 hours. On mine i added one of the B&S hour meters, ( http://www.rcpw.com/Briggs_Hour_Meter.htm no affiliation, just the first web site with a picture) and i try to change the oil between 50-75 hours. Which means that by 80-90 hours it will get done.

To get up to 300-500 hours you will need to be running a engine with a oil filter on it. If it does not have a filter i would be changing the oil every 50-100 hours.

There is also a honda eu2000 user group on yahoo, there DYI information on how to do anything that is possible to your honda there.

http://autos.groups.yahoo.com/group/Honda_EU2000_Generators/

I have a Troybilt 5,500w with a 10hp Briggs runs off of regular gas, all I need to power if the SHTF is my Jetpump,furnace and maybe the frig.