Indicators of a flooded engine could be:
A strong smell of fuel is coming out of the muffler.
The hedge trimmer is not firing.
1
Remove the spark plug.
2
Clean and dry the spark plug with a clean cloth and let it and the top of the cylinder air for a minute. Make sure no dirt or objects go into the cylinder.
3
Put back the spark plug. Check that the spark plug is correctly tightened in its thread.