hopefully its not the rod, you could verify by putting the old wheel back on...I wonder if it could it be the magnet moving up against the roll pins as it passes the coil? I have a arc flywheel that makes noise, its the magnet only noticeable at idle. there is more advance built into the arc over the stock wheel, so yes kickback can occur, especially if the key is partially/ fully sheared. a snow blower pull handle helps alot on hard to pull engines.