why are they so expensive?
I have just found that it is £40 for a new spark plug for the eber' in the 101 ambi. While the plug does have a little bit more metal work round it than a normal plug (there is a metal surround for the spark to earth to rather than just a 'leg') i cant see why it costs so much more than a normal plug?
My eber will just about fire up with the current plug (which has lost some of its earth metal), but it takes a few tries and it backfires a bit before catching (which scares me!). Is this likely to hurt the heater?. Once it is warm it seems fine.