Have you tried opening the concave? Maybe you have it too tight. What about the front of it have you lowered that? Where is your separator grate set at? I would put that at 6. Take a shelled cob and fit that between a rotor bar and your concave bar and see if it fits snug in between. There also do that on the separator grate. Alot of times the cob sizes change with different varieties so thd settings kind of go out the window. Good luck.