Kathy,
Glad to see you back on the forum again. I have not been around much with it being summer up here in the Great White North!
Similar to Frank, I read through every post and also thought, what the heck is going on here!
As he stated, I doubt your issue is with the starter. When they get stuck up in the flywheel like that, it is usually due to a lack of voltage (power) to get the flywheel spinning enough to let it disengage. That does not meant that the starter may not also need maintenance but may not be your issue at hand.
To start, there are auto solenoids, and there are marine solenoids. They look exactly the same, but are very much different. You cannot use an auto solenoid. Verify which one you currently have installed for us.
Next, ensure from Franks wiring diagram that it is indeed wired correct. Use the one for the conversion to 12 volts. Nothing else at this point, pull everything off except what is on the diagram.
Finally, ensure that your battery is fully charged, and load tested. Auto stores do this free. Ensure all your connections are clean/polished and tight. Ensure the wiring is not corroded. It should not CRUNCH when you flex it.
Then, once you have the correct solenoid, all wired correct, with a charged load tested battery, what does it now do?
If you were closer I would come over and help, done it for more than a few Iboaters! A bit of a far drive from Canada though