What should you do if youre ATV stalls submerged in water and you know water backed up in to the motor?

Pull the spark plug(s) and crank the engine to make sure you flush out any water from the combustion chamber. Hydrolocking an engine can blow a headgasket, or worse, snap a connecting rod.

Once you've made sure your combustion chamber is clear of water, you can replace the plugs and start your ATV as normal.