When I was young my Dad worked on Johnson / Evinrude outboards, and a few other orphans in our small town. The NAPA store had the Johnson consignment. (He used to cuss some of them, seems like Atwater-Kent was one, or maybe it was Scott-Atwater)
I learned EARLY that you don't overtighten plugs. Many, MANY outboards, lawnmowers, and other small engines have SHORT reach ALUMINUM heads. It is REAL easy to strip those.
I had an Evinrude twin outboard on my scuba diving boat that someone did that on, but I could never find another head for it to actually fix it.
So one fine day a buddy and I were out doing some diving off the coast about 1.5 miles and on one of the dives we came up to swap tanks and the boat was gone.
We bobbed around looking for where the boat went and finally saw it probably a mile away on it's way to Mexico because the anchor rope broke from rubbing on some rocks (I know because I went back down for the anchor later)
We both had fluorescent net bags that you store fish and stuff in that we could wave to get someone's attention as they were headed into port for the day.
It was late in the day and starting to get dark by the time a boat saw us and picked me up to take me to our boat.
I was trying to hurry before it got dark, and I jumped out of the boat that picked me up and two or three good strokes I was at and in my boat.
Turned the key, "YES!" it fires right up and I nail the throttle and POP!.
That one plug with the crappy threads blew out and went right through the engine cover never to be found again.
I had spare parts and tools in the boat, but there were zero threads in the head, and we limped in on one cylinder right as it got dark enough to need lights.
