18MM sparkplug for lawn mower?
 

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

If emailing, please let me know whether
or not you are posting the same letter.
Change domain to erols.com, if necessary.

meirman wrote:
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

If emailing, please let me know whether
or not you are posting the same letter.
Change domain to erols.com, if necessary.



Similar thing happened to me when I purchased a used snowblower. Someone
had stripped the plug threads in the head, as I discovered when I tried
to start it up.

The most economical fix for me was to buy a new head, gasket and plug.
IIRC it cost me less than $15 for all. A helicoil kit or getting a
helicoil installed by a shop would have cost me more. G

Just my .02,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"As long as there are final exams, there will be prayer in public
schools"

On Tue, 30 Nov 2004 12:07:57 -0500, meirman
wrote:

I think the hole is 18MM now.

Someone has either drilled and tapped the hole for an old style Ford
18mm plug, or they have drilled and tapped the hole for a heli-coil
insert and the insert has somehow come out.

The best option is to remove the head and have it repaired or
replaced, using the correct spark plug.


--
Road Dog
IBA#12795
'99 ST1100

meirman wrote in
:

Is it possible to get an 18MM spark plug for a lawn mower?

Of course it is. http://www.championsparkplugs.com/

Select "Search by Plug Construction" toward the bottom of the page.
The owner's manual or listing for the original plug will give you the
reach and heat range, look up the same or similar in an 18mm.

Note: Lawnmowers aren't real picky about heat range, just stay close to
the original.

meirman wrote:

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.)


Just find a similar mower / engine on the curb on trash day, and
scavenge the head.

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


Sure - just go to your local NAPA store and ask them for an 18MM Champion.
Just make sure the length of the thread isn't longer than the thread on the
original plug so it doesn't hit the top of the piston. I use them in
tractors and I used to use them in my old snowmobiles.
Should be about $1.75.

And does anyone have a brand/number for one?


The original plug was 14MM (a Champion RJ19LM) but it seems the

Meirman

meirman wrote:

snippage
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.

Use the head from one of the other mowers if it the same brand of
engine. (and same or close horsepower rating.)
Just compare them while they're off to make sure they are not different.
You can probably even re-use the head gasket if you are careful taking
it apart..

--
Paul
'91 XL1200
'89 White Pig
"I feel more like I do now than when I got here"

"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


Just weld it shut, then drill and re-tap the threads.

"Oscar_Lives" wrote:
"meirman" wrote ...

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.

Just weld it shut, then drill and re-tap the threads.

Um, he was looking for practical advice. Meirman, forget
Sears, go to an automotive parts place like Autozone or small
engine repairman. They should be able to help you.

- HPT

"High Plains Thumper" wrote in message
...
"Oscar_Lives" wrote:
"meirman" wrote ...

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.

Just weld it shut, then drill and re-tap the threads.

Um, he was looking for practical advice. Meirman, forget
Sears, go to an automotive parts place like Autozone or small
engine repairman. They should be able to help you.

- HPT

What's ****ing impractical about that? I do it all the time. Just weld it
shut and redrill. Use MIG or TIG, take your time to avoid voids (pun not
intended), then drill it and thread it. Use an end-mill to spotface the
seat for good seal.

piece of cake.

meirman wrote:
Is it possible to get an 18MM spark plug for a lawn mower?

And does anyone have a brand/number for one?


Here are some Autolite and Champion numbers and some specifications:

http://www.ramaircraft.com/Catalog/U...olightpg11.htm

"Oscar_Lives" wrote:
"High Plains Thumper" wrote ...
"Oscar_Lives" wrote:
"meirman" wrote ...

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.

Just weld it shut, then drill and re-tap the threads.

Um, he was looking for practical advice. Meirman, forget
Sears, go to an automotive parts place like Autozone or
small engine repairman. They should be able to help you.

What's ****ing impractical about that? I do it all the
time. Just weld it shut and redrill. Use MIG or TIG, take
your time to avoid voids (pun not intended), then drill it
and thread it. Use an end-mill to spotface the seat for
good seal.

piece of cake.

Well, if you think about it, if you have access to a machine
shop with a MIG/TIG welder and milling machine or someone who
is competent and does, yes, could be a solution. However if
it is finding a small engine spark plug that will do the exact
same thing in a larger diameter, I'd think that would be the
easier way out.

- HPT

High Plains Thumper wrote in
:

Well, if you think about it, if you have access to a machine
shop with a MIG/TIG welder and milling machine or someone who
is competent and does, yes, could be a solution. However if
it is finding a small engine spark plug that will do the exact
same thing in a larger diameter, I'd think that would be the
easier way out.

AFAIK, 18mm spark plugs are not particularly scarce, any other solution
seems to me to be more trouble than it's worth.

Ace Hardware carries them for small engines:

http://www.acehardware.com/sm-small-...fi-1305598_cp-
1254884.1255120.html

"Oscar_Lives" wrote:

Or just repair the old head!

Hey, while you got it off, that would be a great time to
mill it down and increase the compression for more power!

I've never seen a pimped lawn mower, may be a first!

- HPT

"Oscar_Lives" wrote in message
news:sO6ud.542317$D%.533628@attbi_s51...

"High Plains Thumper" wrote in message
...
"Oscar_Lives" wrote:
"meirman" wrote ...

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.

Just weld it shut, then drill and re-tap the threads.

Um, he was looking for practical advice. Meirman, forget
Sears, go to an automotive parts place like Autozone or small
engine repairman. They should be able to help you.

- HPT

What's ****ing impractical about that? I do it all the time. Just weld
it shut and redrill. Use MIG or TIG, take your time to avoid voids (pun
not intended), then drill it and thread it. Use an end-mill to spotface
the seat for good seal.

piece of cake.

If hes asking for help on a newsgroup then theres no way he has the knowlege
or equipement to that.
So you think he has a Tig or mig wir with argon gas.
A bridgeport/cnc/knee mill.
A four flute center cutting mill.
A spot drill
A drill for the tap.
Let alone clamping it and indicting off of something to set zero.
All that for some crap old mower.




I work at a machine shop and I still wouldnt waste my time with what your
suggested.
I would use a 18mm plug. Actually I wouldnt waste my time on a
sears/craftsmen mower.
I would work a few hours ot and buy a new mower.