On a 350 kva kohler the generator whilst working cuts off and shows auxiliary fault light shows

That is the specific use of WD40. Spray it when it is warm and the kerosene will evaporate and leave the waxy protective coating behind.

Emergency shutdown operation is required when one of the above conditions occurs in diesel generator set.Diesel generating set itself has an emergency stop button, at this time, press the emergency stop button or quickly press the stop control handle of fuel injection pump to the stop position, the diesel generator will quickly cut off the load, and immediately close the throttle, while the red "emergency stop" light is on. Need to press the button again to delete the emergency stop signal. If there are serious faults or distribution faults, you can also press the button on the control panel, and the unit will stop immediately.

In fact, all faults always give operators some warning signal before spare parts break down or engine damage occurs. So the operators need to be smart, and notice alarm signals (sudden drop in oil pressure, abnormal sound, etc.) and immediately stopping the engine.
Emergency shutdown operation is different from normal shutdown operation.
Emergency shutdown operation.Once the operator finds that there is a serious fault or distribution fault in thediesel generating set, he can press the emergency stop button of the control panel to stop the unit immediately. If there is no special circumstances, we advise users not to stop the unit at will through the emergency stop button.

what you haven't mentioned is the capacity of the genset
( 500 kva , 1000 kva etc ) and the loads that you are applying ( fridge , tools lights stoves , etc) comment on this for a better answer

the unit has gone into over load
The total power requirement has exceed the output of the generator
for example if the generator is a 2.500 kw or kva then it will generate well at 1.8 kva or kw but it will not run forever at 2.5 kva -kw
When a ac is running the power requirement will be constant on the generator and with the fridge as well then the load will be at the maximum out put of the unit.
when the fridge starts again the extra load will exceed the max out put of the generator and it will slow down ( lights dimming ) and eventually go into overload mode
have an accredited electrician calculate your maximum load requirement for an external power supply and then get a unit that is at least 15.. kva kw better that required
generally fridges use 1000watts , ac conditions will draw over 3000watts and any thing else adds up . I am guessing that your generator is only 2500 unit

Make sure you have rated speed and voltage on the out put side.

Check output voltage. Aux fault.

Check radiator coolant fill right to the top, if it has a low level switch or faulty switch I have seen this

Problem solved by poster. good work!

Already solved.

kva = kilo-volt-amps

watts = volts x amps = va

Therefore, 5.8kva = 5800 watts