I took the lower spark plug out and it is black. I didn't have a replacement so I used a car spark plug to tried it. I can't really tell if the cylinder is running or not with the car spark plug but the exhaust is little warm but left side is much hotter. With the OEM NGK the RPM is ~1400 with the car plug the rpm is ~2000 so I guess the cylinder is somewhat running ??

I just got two new plugs from the local part store and will be trying it again tomorrow, thanks.