Originally Posted By: J. A. Rizzo
Like I mentioned, I have mine set up to run at 3600 at 1/4 to 1/2 load, trying to keep the voltage and frequency close to normal to make sure things run right. At 3800 RPMs, the GX390 starts to misfire once in a while, so I have it set up to run about 3750-ish at no load and that seems to be about the right calibration. YMMV. What are you running with it? Backup for house power? Or are you running a specific load like a welder or power tools, etc.? I recommend a tachometer because things that are sensitive to voltage and frequency can be damaged if they're off kilter. If you run AC-powered clocks for a few hours, you may notice that their time is off after a while. They must run off the 60 Hz AC power frequency instead of an internal frequency source. My AC clocks used to run a few minutes slow after a few hours on generator, and that was because the generator originally was set up to run at 3600 RPMs at idle and it bogged down to 3400-ish at half load, so the frequency was low and the clock ran slower. My DC-powered clocks were all fine.
Either your governor or the governor sensitivity needs attention (adjusted or lubed), or it is a darn poor design.
Generators that run at 3600 RPM's should remain pretty much right on, at 3600 RPM regardless of load, 0 to 100 percent of rated. There are a few that sense 0 load and will cut the throttle back to a low rpm. But other than that, if it is a 3600 RPM design it should stay at 3600 RPM.
My cheepo Coleman Power Mate stays right at 3600 RPM now that I set the sensitivity on it properly. New, it was WAY out of adjustment.