My Redmax backpack just died, think the piston went out, I couldn't pull the rope, took out the plug, it spun ok, put it back in, re tried to start it and it started and than started make clunking/knocking noises and that was it. It is 8 years old and served me well. Just wondering if the new C4 technology would be better to go with that a 2 stroke, the Shindaiwa's are nice but no one has them in yet, anyone use them, the new ones are blue. The dealer is about 35 miles away, that's the only bad thing, do they need to have the valves adjusted like the Sthil's after so many hours, I know it is only a one time adjustment. Any suggestions or comments is appreciated.