Okay, a follow on to the issues. I pulled my plugs and found them to be the NGK plugs. This engine was delivered from the factory with these plugs. I first bought replacements at Aircraft Spruce and found them to be the incorrect model of the correct part. Only one model has the metal top that will unscrew and leave you with the threaded post that is required. It is my understanding that NGK chose to not accept the liability for aviation use so now they have a big red X over an airplane and a trike right on the box. Problem with this was they were still manufacturing plugs for an aircraft engine manufacturer so... they quit Rotax. So, either they have actually quit, or they manufacture the plug ( or someone else does ) and label it as a Rotax manufactured part and up the price 10 fold to cover the liability.