Well, there could be a whole list of reasons why an engine would stop running.

But assuming that the engine is healthy, because it was already running with the glow driver still attached, those are the two main reasons why it wouldn't stay running.

You are right, it is just that with the information provided, there are a whole lot of assumptions that have to be made. We don't even know the brand and model of the engine. All we know the glowplug is a no. 8, about the standard plug for a helicopter engine.

About the "other thread" I have no clue on what you guys are talking about. I seem to recall a thread about a damaged glow plug by the same author, but then I have to remind the author to keep the threads to one. Multiple threads just add confusion.

Rafael