Alright, so my battery is fully charged and there’s water in it. When I turn they key, there is a rapid mechanical clicking clearly coming from the starter area, but no attempt to turn over. Stuck solenoid? Bad starter relay? Bad starter? Missing teeth on the flywheel? Seized engine? The Mayan calendar apocalypse?
Possibly dirty batt connections…or an issue with the starter solenoid…Solenoids only do this when there is not enough voltage to power the elctro-magnet coil in the Solenoid…this causes it to “bounce” …but its usually low voltage that does this…which is why I worry about your batt connection cleanliness and also don’t forget the grounds…
Have you put a voltmeter on the batt and gotten a REAL reading…also a reading when trying to crank? All good info…
Voltage read low, and the charger said it was full… bad battery. Replaced and fixed.
VOILA… Guess I nailed that one… No?
You Sir are welcome…Jeez…not even a “thanks” LOL 
I’m very sensitive you know…
Blackbird