I was having a problem with mine wobbling until I put spacers on the shaft between the E clip and the top of the body. Reason it was wobbling for me was because the shaft was traveling up and down when I would spool it up. Apparently the motor was mounted slightly crooked and it would grab the spur gear and shove it up and down at different RPM's. This probably isn't whats wrong with yours but I figured I would mention it.