spark plug equivalents

[RB]

What LM type plugs can I get that correspond to these:

Champion RN-11YC

Prestolite 14-L7B

AC 45-L

Champion H-10

Champion RJ-19-LM (this one may already be one of the LM types...)

I've searched Google and Vivisimo for equivalency charts, and couldn't find
one that has matches for the above:

[Nate Nagel]

Post by RB
Champion RN-11YC
Prestolite 14-L7B
AC 45-L
Champion H-10
Champion RJ-19-LM (this one may already be one of the LM types...)
I've searched Google and Vivisimo for equivalency charts, and couldn't find

Check out the spreadsheet on my web site, I don't think any of the exact
numbers listed above are on there but there are some notes that explain
the coding system for AC and Champion.

What do you mean by "LM type?" I"m not familiar with that designation.

nate

[RB]

}}} What do you mean by "LM type?" I"m not familiar with that designation.
{{{

Oh goodie! I'm not alone, thank goodness.

I don't know what I'm talking about. Here's what I was told by a guy in
another newsgroup recently:

}}} GO to one of the newer style spark plugs engineered for the new
gasolene. They
usually start with an LM instead of J8 or D16 {{{

Never heard of 'em, but would like to learn what they can do for me...

[Daniel J. Stern]

Post by RB
I don't know what I'm talking about. Here's what I was told by a guy in
}}} GO to one of the newer style spark plugs engineered for the new
gasolene. They usually start with an LM instead of J8 or D16 {{{

Pfft. It's this guy who gave you the advice who doesn't know what he's
talking about. There is nothing about the design of Champion's "LM" plugs
that has anything to do with "the new gasolene" (whatever this guy thinks
he means by that). And your J8, while an old number, is still widely used
and readily available as J8C (nonresistor) or RJ8C (resistor) or CJ8
("shorty" version of the spark plug, for tight installation clearance
situations) or RCJ8 (resistor shorty). Its Autolite equivalent is 295
(nonresistor), 305 (resistor), 356 (nonresistor shorty), 255 (resistor
shorty). Autolite's equivalent of J17LM is 456, and equivalent of J19LM is
458. D16 in Autolite is 386.

So, again...what is it you're trying to spark, here?

[RB]

Well, I've got about 3 garden tractor engines that have begun fouling plugs.
The fouling is rich mixture, not oil. They finally get to where they won't
start unless I clean the plugs with a rag. Nothing has changed in the
engines or carbs, so I thought possibly it has something to do with regular
gas. The question was: can I go one heat range higher to counter the
fouling. The answer was to use these "LM plugs for newer gas". I have no
idea what newer gas means, or what design differences might be in the LM
plugs.

Good info you gave. Thanks.

Think I'll just try one notch hotter plugs of the same kind as the ones in
there.

[Daniel J. Stern]

Post by RB
Well, I've got about 3 garden tractor engines that have begun fouling plugs.
The fouling is rich mixture, not oil.

OK...so...fix the problem! You'll find it in your carburetor(s). You don't
mention the manufacturer(s) or model(s) of these engines, but you can find
brand-new carburetors (often updated versions) to suit virtually any small
engines on Ebay for very little money, or for somewhat more at an
authorized service center. And you might well not even need to go to that
length; if the inlet needle and seat on your carburetor(s) are worn, torn
or hardened, that alone could easily cause an overly-rich condition. A new
needle/seat comes with a carb rebuild kit. And it could be even simpler
than that -- be advised that most of these carburetors have *two* mixture
adjustments; one for idle and one for high speed. If either or both is
maladjusted, the spark plug will quickly fuel-foul. Of course, you must
also make sure the choke opens fully.

Changing the spark plug's heat range or type will NOT fix the problem --
any other spark plug will also fuel-foul. The guy who said LM spark plugs
are "designed for newer gasoline" is full of compost.

Post by RB
Nothing has changed in the
engines or carbs,

They wear with age and use.

Post by RB
Think I'll just try one notch hotter plugs of the same kind as the ones in
there.

No, you're really barking up the wrong tree here. Find and fix the
*problem*, then the symptom will go away.

DS

[Bill]

Post by RB
Well, I've got about 3 garden tractor engines that have begun fouling plugs.
The fouling is rich mixture, not oil. They finally get to where they won't
start unless I clean the plugs with a rag. Nothing has changed in the
engines or carbs, so I thought possibly it has something to do with regular
gas. The question was: can I go one heat range higher to counter the
fouling. The answer was to use these "LM plugs for newer gas". I have no
idea what newer gas means, or what design differences might be in the LM
plugs.
Good info you gave. Thanks.
Think I'll just try one notch hotter plugs of the same kind as the ones in
there.

Have you checked to make sure the air cleaner isn't clogged or the choke
partially on?

[Daniel J. Stern]

Post by RB
Champion RN-11YC
Prestolite 14-L7B
AC 45-L
Champion H-10
Champion RJ-19-LM (this one may already be one of the LM types...)

Well, it depends what you mean by "correspond". Heat range?
Reach/Thread/Hex? What is it you're trying to do here?

"LM" is Champion's designation for spark plugs designed specifically for
use in small 1- and 2-cylinder aircooled engines such as those found in
*L*awn *M*owers. They have a standard (non-projected) tip which is fine in
a sidevalve aircooled engine but not at all appropriate in most any OHV
auto engine made in the last four and a half decades, and a side electrode
that extends only halfway across the center electrode, which in theory
better resists the bridge fouling that can occur under certain conditions
in small aircooled engines.

Again, what is it you're trying to do?