My starter is clicking but wont turn all the way over. This is the 3rd starter i put on and still am not sure how many shims to use. I didnt pay attention when i took the first one off and now im lost.

If your using different shims everytime I doubt the starter is the problem.Does it engage and turn slow or does it spin fast like the small gear is not engaging on the flywheel Have you cleaned the battery terminals. Have you tested the battery. A simple test you can do at home on the battery is hook up a 12 meter and if the voltage goes below 10v right away when you crank and the engine does not turn, then the battery is shot. Also alot of times the ground cable on the battery will go bad so a simple test for the battery terminal is use jumper cable and clamp to the negative side of battery and clamp the other end to the engine. This will give the battery a direct ground.