Starter keeps starting!...

Getting ready to break in the new small block for my power wagon build and the only thing I never checked was if it would actually turn over.... Well I hit the starter and it cranked right away I let go of the key and it kept going! Yikes I ran and grabbed the negative wire off...
I touched it back and it didn't do it again.... Of course I had to try the second time to see if it would do it again but this time prepared to run over and grab the negative wire not let it crank too long...
It did it again...
My first suspect is the brand new Speedmaster mini starter... Chinese crap!..
I'm pretty much done for today but looking for ideas for tomorrow. When I looked through other threads I like the idea of loosening the starter a little bit to see if it's just binding and sticking.. I don't want to go at this too many damn times as I haven't broken in the motor. I don't want to be cranking the hell out of it...
I'm not sure if I could fit a factory starter in there but I have plenty of those...
Thank you for any good ideas...

I am such a helpful guy, I will offer my superpower to assist your situation. Send me the starter. I have a well-documented ability to work on things that work, and make them not work. Starter won't stop starting? Send it to halfafish, he can ensure it will never work again.