2000 GT40 Starter Going bad

Hello I tried doing a search for this and had to give up, Yesterday on my new to me 2000 Ski Nautique 196 the starter motor refused to engage. It seems like the solenoid \ starter relay on the side of the starter was at fault. I came to this conclusion from the rapid clicking sounds coming from it (see attached picture with arrow point to part). I was able to get the boat started by the old tried and true method of hitting it with a hammer.
Now my questions: Is it possible to just replace this solenoid \ starter relay part? If so, what is the part number? (Actually I having difficulty confirming this part's name solenoid or starter relay?)
If not, can I just replace the starter with one from a Ford Truck, etc. If so, what do year, model truck do I tell them at AutoZone?

Thank you in advance.

Brand new battery - also tied jumping it from another running boat - same result clicking from solenoid. Disconnected jumper cables and hit the solenoid part of the starter with a hammer and issue was resolved.
Long story short, I am pretty sure its the solenoid \ starter. Now the question is how do I repair it for the least about of $$$.

http://www.jegs.com/i/Optima-Batteries/753/9052-161/10002/-1
12.8

Ok I just need to know if their is any issues running a auto starter? They are only 90 bucks.