My friend and I have been using an older model jiffy auger, all I know is that it is 8in. Recently, something terribly wrong is going on and the engine runs absolutely fine but the blade stopped turning. It does not end there, we had another jiffy loaned to us and only a couple of years old and on the last hole the same thing began to happen. Is it a bearing or clutch and how do you fix it, and is there a way to prevent this. eg. drilling technique? Thanks for any suggestions