sounds like someone's already drilled and tapped for a HeliCoil and the
insert came out.
if you're friendly lawn mower mechanic won't loan you his tool kit and
sell you a $2 insert, you can probably rent the HeliCoil spark plug tool
kit. Hardware store sells a kit for $40 with a few different height
inserts.

My mower shop guy loaned me his full HeliCoil kit with a healthy cash
deposit and a promise to be right back. Free tips and tricks too.


"meirman" wrote in message
...
Is it possible to get an 18MM spark plug for a lawn mower?

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.

Thanks





Meirman

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