Hello,
I bought a 1937 Sears Water Witch for display in my cabin and had it shipped to me. The spark plug was damaged and bent in transit and I’d like to get another used one that’s period correct to replace it. Don’t care if it works or not, just has to look right. The plug was a Stromberg 7. Can’t find an identical one on eBay. I’ve seen a few vintage plugs that look like they would work but it’s hard to tell from pictures. The ones I’m looking at are advertised as 18 mm plugs. If this is the diameter of the threads then that seems to be close. I measure the outside diameter of this Stromberg plug to be 17 mm but I admit there’s some error in that measurement so it could be 18 mm.
If 18 mm refers to the size of wrench or socket that’s needed for the plug then that’s definitely not the size. Looks like a 25 mm or 1" wrench is needed for this plug. This plug is bigger than the modern standard size spark plug.
Is the plug I’m looking for an 18 mm? If not, what is the size or type that I should be looking for?
Thanks
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