The gen is probably to small to run ( start ) the A/C.What is the amperage draw of the A/C unit at start up. It can be up to 10 times the running amperge.
You did not state what size generator or the btu rating and locked rotor current and running current rating of the A/C.
It is hard to trouble shoot with out detailed information.
The ratings can be found on the equipment data plates.
JACK ( KZ5PZ ) & SHIRLEY
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