You may have a weak coil that stops working due to heat soak after the engine is shut down. Often times, after sitting for 20-30 minutes, the coil will function again once it has a chance to cool down.
While the coil is overheated and not providing spark, the engine will flood.
Charge the battery and drive around the block as many times as it takes for the engine to reach operating temperature and then park it where you are going to work on it. Shut it off and wait 10 or 15 minutes to see if it fails to start.
If it fails to start, check for spark. If no spark, buy a new coil and see if it starts.
