Just a thought: YOu said it runs for a while, boggs down (At which time something is shutting off power) But the generator revs back up and eventually power is restored.. How long does that take?
Answer: 30 seconds to 1 minute: Auto transfer switch sees lowered voltage and drops out.. When voltage returns timer cycles and it re-engages generator
2-3 minutes: Do you have a surge guard/power MONITOR system like a Progressive Industries HW-30 or 50 C? If so see above but different device doing the cycling.
By the way, this is known as working as designed in both cases.
NOW: what is causing the Generator to "Bog Down" epically if Onan cleared it?
Found out something a while ago...I have two Air conditioners on this house, they draw, per their label 13.5 amps.. Ok, so why did one of them suddenly start tripping a 20 amp breaker? (Folks, do not worry about that I fixed it)
I got out my clamp on meter and monitored current, sure enough, after the A/C had been running a few mintues current was climbing well beyond 13.5,, in fact, beyond 21 amps So it was NOT, as I initially suspected, a bad breaker, device was working as designed.
Went topside, popped the outer shroud off the A/C.. Popped the inner cover off the condenser (HOT) coils.. REMOVED all the crud that had collected on said coils.... Replaced covers, Reset breaker,, Measured sustained 13.5
IF you are running the Roof A/Cs. and they need cleaning, then after a few minutes of operation they too may start sucking excess amps. and if your ONAN is like mine, a 5500 with two 30 amp breakers, a BALANCED load can bog down the generator BEFORE it trips the breakers.
So that's where I would start looking,, Clean the A/C to reduce generator load.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times