Bob
The service manual is available on line @
http://www.cumminsonan.com/www/pdf/m.../981-0530C.pdf
The parts manual is available @
http://www.trekdocs.com/Onan%204000%...%20first43.pdf
I have had this problem twice with my onan. KY . first time it was the control assembly this time it's a short in the rotor.
If you not a DIY type and want some one else to repair it or need parts perhaps you could contact Rich Biebel on this form.
Rich informed me that these little generators are tough on brushes too and the motor will not run if the generator is not producing 120 volts.
Be forewarned that onan parts are not cheap $$$$$.
If you want to trouble shoot it yourself download the manual and start reading.
To get the rotor out you'll need to turn a 1/2" X 7-7/8 long rod stock down to .450 dia. But you can chech it with an ohm meter first . section10 of the manual will help you in trouble shooting it as well.
Hope this helps.
