I was running my DLE 30 last night and it seemed to be vibrating a lot. This is only the second time I ran it, but is this common? I was running a well balanced Xoar 19-8 laminated prop. It seemed a little lean on the low end and richening it did seem to help with the vibration. It still seems to vibrate more than I would like. Could I be getting pre-ignition, and if so how would I know and how would I solve it if I was?