Well no. In an emergency, the lead core in the plug melts and the boiler steam put out the fire if there is a lack of water above the lead. I needed to remove the plug to check it, that being good practice on an annual basis. Local heating with a torch might have helped shift it (would certainly melt the lead) but bear in mind that when running normally the fire itself can be white hot, so probably unlikely to make much difference.
I have now got a BSPT (tapered) plug to put in the re-tapped hole in the spring. The engine is all tucked up for the winter now anyway...
Tim
