Cranking issue please help!
 

So I have a 50CC KIDS Chinese quad. The starter went out possibly due to me using a car battery to try to get it started. I replaced the starter with one off eBay I could never really get it to crank fast enough to start the quad unless the spark plug was out also the starter gets very hot. Does anyone have an idea? Am I breaking these starters by using a car battery? Is there a better starter I can buy? The starter is the two bolt starter it cost 29$ on eBay. Another note I have added extra grounds for the battery and starter neither helped.