UU lowvoltage error code residential generator

it is not any kind of car or truck,so moved you to portable elect gas generators.
does it burn gas/petrol or LPG?
with engine stalled, oil lamp on is 100% normal
but never at the time of stall (or just before)
the oil pump runs off the crankshaft is why.
new spark plug is cure. i bet.
or use chock longer.
carb, gasoline , petrol.
if spark tip is in raw fuel , turn off chock and crank it dry.
the gen has many buttons switches make sure all are set correct for sure on./off .
is it elect starter or hand cord cranked or both?

Check gaskets / seals / piston rings as it sounds like oil contamination is fouling the plugs.

UU is generator under voltage. Check to see if it does it without laod also. if it does you will need a pro to check and ohm the rotor and stator for shorts

Check the oil safety switch maybe it is bad. It will stop running if low on Oil or wont start.

Here is the code explained direct from Kohler's manual. I'd disconnect the generator load first.
UU Undervoltage Shutdown occurs if the voltage falls below 80% of the nominal system voltage for more than seconds. Check wiring and connections.
Reduce the load and restart the generator set. —
Check wiring and Check controller configuration, system voltage
and frequency (parameter UU).

Check AC voltage and adjust, if necessary. 5.7
Replace the SCR module and test voltage again. 4.9
Separately excite unit. 5.2
Check stator continuity

See web site for manual :http://www.kohlerpower.com/onlinecatalog/pdf/tp6196.pdf

Means that the engine has turned over for too long without starting. It times out to protect the starter and battery wiring.

U need to make sure that the relay driving ur auto start stay closed all thru the crank cycle.

Measure voltage drop across the far ends of the fuse wiring (should measure zero), as one of the wires or it's connection to either end of the fuse may be open. Check the battery negative grounding connection at the frame. If all ok, you may need to find a wiring diagram for the machine. Does this unit have a low-oil-level switch which will kill the engine if set?

call koler but ui think is meant high heat as in the thermal circut is shuting you down or low oil
could be a couple of things best bet call kohler

caborator needs cleaning