And does anyone have a brand/number for one?
The original plug was 14MM (a Champion RJ19LM) but it seems the previous owner drilled out the hole and it is now about 18MM. (I hope it is exactly 18mm, but I won't be able to tell until I buy a plug.)
The recommended 14MM plug has what I think is a short reach. The threaded part of the plug is 3/8" long, and if one includes the electrodes, the distance from underneath** the washer, past the threaded part, to the end of the ground electrode is 1/2".
**Maybe the "reach" is measured from above the washer. If so, both lengths should be 1/16 inch less.
I bought this Craftsman lawnmower second hand, and when I got home, the mower looked even nicer than I thought, but had no spark plug. I took plugs out of my two old mowers (which don't work or don't work well) and the hole was too big for them. I went to Sears and all the plugs they had for sale had the same size threads as the ones I had tried, 1/2 inch in diameter, which I guess is 14MM.
I think the hole is 18MM now.
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