I have only had one plug that would glow and not run the engine in 10 years. Don't hold any one thing suspect. What you said is going on could be bad fuel too. I had some fuel that was about 7 days old from the hobby shop. I don't know if I left the lid off too long or what, but Glow Fuel has the natural ability to absorb water from the air. (That is why you use after run in an engine before you put it away -- stops the rust and crud as well as other things) If your fuel is bad your engine may not run after you take the battery off the glow plug. If you change the glow plug and still have the same problem, drain the tank and get new fuel.