Sounds like a lack of preventive maintenance. When was the last time that you took the one screw out of the flue vent in the back of the fridge
, (accessed through the bottom outside removable vent cover,) and cleaned out the burner tube with a small brush and some compressed air? Those burner tubes get crapped up over time with soot, flaking metal, bees and spiders trying to homestead in there. If it isn't kept clean, you will start experiencing problems like this. This should be done each spring before camping season, or more often if it is used on propane
Turn off the gas, turn off the fridge.
To remove the burner orifice you will need:
Both a 10mm and a 15mm open end wrench,
#2 Phillips head screwdriver,
Can of spray brake cleaner.
Can of compressed air, or access to a compressor with a blower nozzle.
Take the screwdriver and remove the sheet metal burner shroud screw and remove the shroud, in the lower right on the back of the fridge. (Bottom Picture)
With the wrenches, remove the gas burner tube and blow out the burner tube venturi with compressed air. A brass shotgun bore brush on a short handle works pretty good for brushing stubborn debris out of the venturi.
Remove the small burner orifice and soak in solvent, or use spray brake cleaner. Allow it to air dry. Visually check it to be sure that the orifice is not still obstructed, usually shining a small flashlight through it will help to check. Do not use anything, (pin, paper clip, drill bit, etc. to clean out the orifice. If you screw up the diameter of the orifice, you will be replacing it.
Just soak it some more if it isn't clean yet.
Reassemble parts in reverse order.