If it's genning the correct voltages to the receptacles, the problem is most likely in the ATU (auto throttle unit) unit only, not the stator!
The reason I say this is the ATU unit is a current sensor coil that turns off and releases the throttle when more than 1 amps flows through the sensor coil to the single receptacle or receptacles!
The EX5500 does not show the ATU unit in the service manual, but their are about 6 manuals and they go by serieal number range, but I see a schematic and AUTO throttle description in a EB5000X manual!
If you want to see the diagram, etc, I can send it to your regular e-mail address if you PM me with such!
Basically, when you turn the ATU on you should see the solenoid pull the plunger in so as to reduce the throttle to approx 2200 rpm engine speed! (the engine speed is adjustable for the ATU speed by a linkage or idle stop screw!
Check the solenoid on the auto throttle unit and it's connecting mechanical links!
(and make sure the governor spring is in it's proper location) I do not know the exact DC voltage being applied to the solenoid by the On switch, but you could also test and see if the solenoid has a DC voltage APPLIED WHEN THE SWITCH IS ON! (and check the solenoid coil for opens, etc) I suspect the voltage is approx 12-20vDC but this is just a guess-estimate! (main thing is check for a voltage across the coil when the ATU switch is ON!
Post the serial number range of your unit! Service diagrams go by serial numbers! I have some service diagrams for the EX5500 but not sure if the manuals has any ATU service info! (I can look if I know your serial number range!)
You may already know most of this but good info in this link! http://www.mayberrys.com/honda/generato ... ration.htm