The fluid in the cylinders cannot be compressed. Locking the engine=hydrolock. This can happen several ways, gasoline could flow in from your fuel system, water may run in from you flame arrestor bolts washer gasket and if the boat was being launched at the ramp sometimes people forget to take...
Hydrolock will be relived, be careful and turn off the ignition by using the kill switch in the event the engine cylinders are full of gas, you need to be careful and protect yourself and the boat. Have a fire extinguisher, smell the spark plug, look for water on plug.
Once you've repaired your starter, I would remove a couple of spark plugs before trying to restart the engine. This may help figure out why it broke and keep the starter from being damaged.
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