Quoted:
I have had a champion 3500/4000 watt generator I bought new for about 2 years now. It starts right up on the third pull as a rule when cold and runs fine under load and always has. If I shut it down, it often takes 5-6 pulls to restart but always does. It is quite smooth. However, when there is no load on the generator, it has always idled with a lot of loping/surging. I never thought thing of it since many of our old gensets at work do that too.
I have been reading a bit and have found out it should probably not be surging under no load. Anyone have thoughts on whether this is a real problem and if so, how to fix it? Thanks.
Check carb for blockage in the midrange fuel ports.
When the throttle is closed, idle ports are behind the blade. (engine side)
As the throttle blade is opened slightly, it passes the midrange ports. There may be 2-3 holes or a slit.
Slightly heat and bend the end of the red straw that comes with the carb cleaner; so you can get it in there and flush crud back through the carb.
On second thought..........
Before going through that, grab the throttle linkage (the one that runs to the carb after the governor); and force the engine to run at the right speed with no load. If it runs nice there might be spring/linkage issues. If it misses or changes tone like it is running lean, then carb work is in order.
There's also a mega thread at RV.net that seems to be the center of the Champion generator universe.
Found it.
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/15131645/srt/pa/pging/1/page/1
Use supreme Google fu to narrow "surging generator" results to that site.