Re: Broke a sparkplug, and how!!!
I am not really sure about the chemistry/physics involved but if you have 2 metals in a liquid medium (esp saltwater) the less noble (like aluminum) will be eroded in favor of the more noble (like stainless steel). Now in this boat you have steel shell sparkplugs in an iron head, so what you were dealing with is most likely just plain old rust, not galvanic corrsion (unless cast iron is less noble than the steel). I am not sure of the effect of the antiseize (has copper in it) in combination with the iron head steel plug. I have found that just using some grease on them seems to keep the corrosion down so they are easy to take out. As an example, since I used to use it (antiseize) on my cars with alu heads, I also used it on my 4.0 Jeep motor (cast iron) the last time I did the plugs (2 yrs ago) and it didn't seem to help, in fact it seemed a little more difficult to reomve them that the first time (from the factory plugs, no antisieze). All of my 2 cycle stuff (blower, snow blower, weedwacker) have alu heads, I don't use antiseize on them, and no probs getting the plug out (maybe the oil in the fuel mix helps). Oh well another one of those little mysteries.
