Wire diagram 0611-1267 or service manual - Onan Microquiet 3600 & 4000 Generator my wiring harness was chewed by rets need to repair harness please need above wiring digram.

Please contact your supplier, they have wiring diagram for 2800 onan generator.
But if you would like to learn more about other kinds of generator, such as diesel generator, gasoline generator, please visit at www.dieselgeneratortech.com.

Found this manual on the internet
1103_ky_spec_p_install_2015.pdf
It seems to have wiring diagrams.
Is this OK?

Onan's website has them. I don't think you can get one for free, though.

Check the ignition circuit, and trigger coil for correct resistance on the trigger coil, and the ignition coil. The trigger coil is a small module on the engine shaft near the flywheel.

Check the pickup tube in the vehicle, the fuel pump is suspect. If you check the fuel pump pressure and it is ok, then try installing a test check valve between the fuel delivery hose to the generator. If it solves the problem the pump is losing it's prime internally, so replace the fuel pump.

contact www.advanced-power-technologies.com they will help you

If there is no spark, the ignition module may be bad, or the wiring to it. Have the module ohmed out. Also the magnetic trigger assembley that is on the rotor that sweeps past the ignition module maybe broken. If they check ok, suspect the control board

That sounds like the reed valve sticking or dirty.
You will need to take out the reed valve, clean and re-install. Be aware that a small amount of oil is common, also do not over fill the oil. The full mark is hot. Too much oil in the crakcase can build up pressure and keep the reed valve open.

Give me to full model and spec # and I will email you a service manual.

Remove the air cleaner and inside near the throat of the carb is two bolts holding the carb to the intake remove these. Unhook the fuel line and twist the carb to allow the linkages to remove.