On these cheap 5.5kw units, is the voltage adjustable? I have a Briggs Mod 030324 and I an not finding any maintenance documentation on the web so far. I did adjust the governor to get the frequency up to 60, from 57 but that did not do much for the voltage that seems to be 108-110 with a moderate load. That makes the motors harder to start and exacerbates the locket rotor problem.
A local generator guru, and small gas engine guy said on most low end gensets the 120 voltage is nominal with a whopping 10% under (108) and 2% higher (124). He uses IMHO high end testers and I tend to believe his info.
Yeah, it's adjustable on cheap gensets: if you want higher voltage, plug in less; if you want lower voltage, plug in more! There may be better adjustments on some models, but I haven't seen any on units this small; the waveform quality is pretty terrible, too. Higher end inverter gens are way better, but you'll pay for it.