If you haven't been able to get the engine to start then you probably got fuel sitting inside the motor attracting moisture. That's fine if it doesn't sit to long AND in dry air. But, if you have fuel in the motor and it's been sitting for awhile then even AC can't help you.

My experience has been that if work or other obligations keep me away from the airfield for an extended period of time then I pull the glow plug and work some afterrun in there and spin the motor over with starter. And, if it sits longer than a month I pull then engine fill it with afterun and put it in a Zip lock baggie.

May seem like alot of trouble but after ruining a couple of OS motors I learned my lesson.

Now that I am flying at least 3 times a week all's good!!