If am understanding you and understanding the print.
After setting up conditions and based on the last time i did this test :
K12-12 was 0 volts
K12-14 was 23.4 volts
and so on.....
I will do the whole test again tomorrow after adding enough fuel to clear the No fuel interrupt again and post the results.
If i still have 23.4 volts @ K12-14 then (in order) as you said this is my 1st circuit problem to trace out and diagnose/correct.
I followed the wiring diagram from K12-14 to S1-3 from there to P4-7 which is a terminal @ A2 Malfunction Box
from here i get lost.
If P4-7 is a "fault as in ~23 vdc" output back to K12 then is that voltage corresponding to and input signal from the opposing P4-2 ?
P4-2 traces back to J7-12 via 34B18 and i reach a dead end.
Or is P4-7 just outputting voltage based on an input from any other bad actor(s) via the inner workings or malfunction within A2 box ?
Trying ask a sensible question with a pretty shallow knowledge base of the workings of electrical creatures.
I do have a friend that is a very good electrical and mechanical engineer. He is a little hard to hook up with for various reasons. I don't want waste too much of anyone's time trying to get me up to speed on all this. This method of remote troubleshooting by text can be long drawn out by its nature.
I do have a much better understanding than I did just a few days ago though.
Also think this generator is in pretty good shape once this problem is fixed and i may need to upgrade the controller as suggested in other posts.
All the linkage is still marked and sealed in place, very clean inside, starts right up, no smoke .... surely nothing else could go wrong !!!
However it gets worked out i will post the results for the benefit of any others that come across this problem.
Great help. Thanks again.