1) Run as few other appliances as you can on AC when you want A/C. Reefer & water heater on propane, etc. Start the A/C fan on low, wait about a minute before putting the thermostat down to where the compressor kicks in (less starting surge).
2) See your owner's manual for maintenance schedule. Maybe the fuel or air filter or spark plug are past due for changing. Also check manual to see if you have a spark arrestor screen in the exhaust that may need cleaning.
3) Ask the moderator to move this thread to the tech forum where some gen techs hang out sometimes.
Jim, "My psychiatrist said I was crazy. I said I wanted a second opinion. He said okay, you're ugly, too."