Have a question regarding my JD 43 sheller, I went with dekalb corn this year which shells better than last years croplan. I'm feeding this in with an elevator, problem is i'm getting some cobs coming out of the sheller with kernels still on them, I've adjusted the cob door tension and that hasn't helped much, i'm feeding the machine the equivalent of a scoop shovel then waiting about 4-5 seconds and putting more in. I saw a video on youtube where a boy was feeding one so fast that the cobs were falling back down the cob elevator and his was coming out totally clean, any ideas? my corn is around 18% moisture.