starter/battery/ voltage problem no start

[gcha1727]

I have twin 787 on my challenger 1800. One motor starts. One does not start.

The motor that does not start make a click during crank (sometimes). If I bypass the solenoid to "jump start" it I get the same results. Voltage at my battery falls off to 7-8 volts while cranking this motor. Voltage was taken at the starter and the battery. I can turn the motor by hand. I bought a new starter and it did not help.

So far I did the following without it helping;

replaced starter with new one.
Pulled the starter from the good motor and tried it.
Replaced both power and ground wire from the good side.
replaced solenoid

Any ideas thanks

 

[gcha1727]

After spending more time on the motor I found out it was hydrolocked. I think hydrolocked is the correct term. I was able to turn the motor earlier by hand but now Im second guessing if I did it with the plugs in or out. Either way, the motor cranked over With the plugs removed.