I feel weird leaving the plug in when I put the engine at full speed because it doesn't smoke as it should. But then when I take it out (at open throttle) the smokes starts coming out of the muffler as it should. does leaving the glow stick on the plug for a few extra seconds while you are fiddling with the engine running damages the engine?
I remember once forgetting to remove my glow driver from a plane and didn't notice it till I was landing.....First off I'm surprised the thing stayed on the entire flight, and 2nd' I sure was wondering why my engine was running so well
Leaving the glow driver on while you tune is not a problem at all. Usually if your engine dies when you remove your glow driver means that you are rich (plug is getting too cold). As cheap as glow plugs are, you might want to just replace it to be on the safe side.