Kpmilke

I have an automatic 2002 Subaru Forester, and I am having trouble possibly with the starter. I replaced this starter a year ago when the old one stopped working. Recently the car has had issues starting. All I here is a spinning noise which sounds like the bendix spinning but it does not sound like it is engaging the fly wheel. I have tested the starter to make sure the bendix was working by separating it from the engine while all the wiring was still hooked up. Upon turning the ignition on, the bendix drive pops out and starts spinning, just like it is supposed to. I can't find anything wrong with the starter, and there is nothing foreign up against the flywheel to block the bendix drive from coming out and grabbing the flywheel. I checked the teeth on the fly wheel and they were not worn or broken. I worked on the car for 5 hours today and out of the 30+ tries to get it started, it started twice. I am clueless. There is some wear on the front of the teeth of the bendix, is it possible that the bendix isn’t engaging the fly wheel enough, do I need to shim the starter? If anyone has any ideas, I would be most greatfull.