Our Onan 8kw genset has three sensors, each able to shut down the engine. High coolant temp, high exhaust temp, low oil pressure. Ours has a breaker that trips that must be reset on the control panel. A few things to check:
1. Even though the sea water strainer is clean, are you getting good water flow out the exhaust discharge port? An improper placed strainer cover will suck air, preventing insufficient coolant water flow.
2. What micron is your fuel filter? Ten should be fine. Our original was two, which is too fine.
3. Are you getting good fuel flow from the engine side of the fuel filter? A restricted flow will cause the engine to shut down.
4. Any intake air flow blockage, such as an air flow filter?
5. You may need to connect an oil pressure gauge to verify oil pressure.
Diesel engines only need air and fuel to run, but other factors may cause it to shut down. Ours shut down twice before: a clogged seawater strainer and a clogged fuel filter.
The Xantrex charger/inverter or battery bank should not affect the genset from running. I’m assuming that the genset is generating 120/130 volts ac when running?
Please let us know if you find anything.