Pull the spark plug out and pull the recoil a few times to expel any water in the combustion chamber.
Check for spark while the plug is out.
Pull the dipstick and see if there is any visible water on the stick or floating on top .. if you see any or are in doubt then drain and replace the oil.
Replace the plug and try to start it ... if it wont then pull the plug and pull on the recoil again.
Replace the plug and give it a shot of starting fluid.
If it ran before it will run again.
Don't let the water sit in there too long as it can cause problems.