I see lots of guys referring to "solid core plug wire". I'm sure they know what they are talking about, but it may be misleading to others. It isn't actually solid core, but is stranded metallic "wire" core. What everybody is trying to convey is that cars built in the last 60 or 70 years or so use a carbon-filled string as a core. That stuff is no good for outboards. Look for "wire" wire at lawn mower shops, tractor shops, motorcycle shops, and yes even outboard shops. Some auto parts stores stock it too, but others will give you that blank stare.