[Will-I-Am]

Not sure exactly what I have been doing wrong... I have burnt up 4 starters. They eventually start to just grind the teeth of the flywheel (which I have just replaced also now because the teeth were gone). I have no idea what I am doing wrong other than perhaps I keep getting a wrong model starter?(boughten used from craigslist)

Basically I need a 2g awd starter.
And please let it be the last that I will need!

Looking the pay around 30 for it.