I have a ZDZ80, but since it hasn't given me any trouble, I can't comment on any problems. I use the normal starting method not the 5-5-1. Only problem was a bad ignition battery. The previous owner put in a really small battery in an effort to save weight for IMAC. A new higher capacity battery made the starting problem go away, and the plane still flies great with the extra ounce of battery. ;-)