Spark plug cross reference needed
muncybob
Posts: 3,112
Got a spark plug conundrum. My Dad's circa 1965 push lawn mower has a plug in it with green lettering "LM7". Neither the NAPA or Auto Zone stores could find a cross reference for it. I also struck out doing searches. Would anybody have a source to solve the mystery?
Yep, my name really is Bob.
Parasound HCA1500A(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Marantz UD7007, Polk L600, Rythmik L12 sub.
Parasound HCA1500A(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Marantz UD7007, Polk L600, Rythmik L12 sub.
Comments
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Did you try a small engine/lawn & garden equipment place? Find one that's been around for a while, and they've probably got some NOS from the '60s in a multi-drawer cabinet in the back room (lauan wood paneling, ashphalt tile floor and all).
LM7 sounds really familiar to me, but I've got no insight for modern equivalents.
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Don't take experimental gene therapies from known eugenicists.
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Another way to search for a correct modern plug might be year make and model from any data plaque on the mower.George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
According to Google LM7 relates to a Chevy engine
- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit. -
According to Google LM7 relates to a Chevy engine
That'll speed up lawn cutting considerably, I reckon -- not to mention make cutting wet or tall/dense grass easier.
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Trey, get your search engines straight. You didn't Google, you Binged! Never trust Bing...
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Trey, get your search engines straight. You didn't Google, you Binged! Never trust Bing...
Is the past tense of to bing indeed binged? Maybe bang? or bong? or bung?
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I'd guess it is something like this?
https://www.ebay.com/itm/395608245876
(after posting, I realized this is the same item that xschop linked above)
That doesn't seem to help with any of the cross-reference charts though. It might be easier to search by the engine in the mower or go to a local dealer that sells lawn equipment: Deere, Stihl, Gravely, etc. I'm sure they have something that would match.
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mhardy6647 wrote: »
Bing'd? -
Well there's the info. you needed thanks to marc hardy
Replaces: Champion J-17LM, CJ-8, J-8, AC LM46 CS45
Plug those into cross reference charts if you can't get those.
https://www.lawnmowerpros.com/spark-plugs/spark-plug-cross-reference-chart.asp
E3 plugs are good. Champion J-17LM plugged into E3 site gives:
https://www.e3sparkplugs.com/products/e3-10-spark-plug?rq=yr_all-other-small-engine-equipment~mk_champion~md_j17lm
Champion CJ8 gives:
https://www.e3sparkplugs.com/products/e3-12-spark-plug?rq=yr_all-other-small-engine-equipment~mk_champion~md_cj8George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Got a spark plug conundrum. My Dad's circa 1965 push lawn mower has a plug in it with green lettering "LM7". Neither the NAPA or Auto Zone stores could find a cross reference for it. I also struck out doing searches. Would anybody have a source to solve the mystery?
Seems like back in the day, most mowers were based on a similar flathead design and they mostly all used the same plug. That's why you see Mark's photo says "fits 90% of mowers". The Champion J17LM looks similar and advertises the same claim of fitting 90%.
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I use those E3 spark plugs in all my small engines, they work very good!
I actually was looking at the site earlier trying to cross reference as I had seen the LM7 on one of my plug packages and couldn't remember which one it was. -
One might also consider having your dad loosen up his grip on his wallet and get a new mower ! 🤔
Those silver certificates are still legal tender, so tell him he's worth it 👍🤗Sal Palooza -
Just hanging on to the mower to remember my Dad as he was so proud of still having this grass cutter for so many years. I cut the grass many times with this little cutter.
Looks like we are onto something with the info you guys provided, those pics look like the plug(sans the rust and grime).Yep, my name really is Bob.
Parasound HCA1500A(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Marantz UD7007, Polk L600, Rythmik L12 sub. -
What kind of engine does the lawn mower have? Briggs and Stratton? Tecumseh?Expert Moron Extraordinaire
You're just jealous 'cause the voices don't talk to you! -
Briggs. The mower brand is Rugg with no identifying plates. Engine just has generic info on it.Yep, my name really is Bob.
Parasound HCA1500A(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Marantz UD7007, Polk L600, Rythmik L12 sub. -
Original B&S Spark Plug number was 799876
Current number is 591868
https://www.sparkplug-crossreference.com/convert/briggsstratton/799876
https://www.sparkplug-crossreference.com/convert/briggsstratton/591868
https://shop.briggsandstratton.com/products/briggs-and-stratton-591868-compliance-spark-plug
That should be the spark plug you are looking for. Compare it to what you already have if it matches the length of the threads and the height of the ground lead protrusion, it'll work.Expert Moron Extraordinaire
You're just jealous 'cause the voices don't talk to you! -
Also, is it a tractor or a push mower?
Found this info: https://www.tractordata.com/lawn-tractors/tractor-brands/rugg/rugg-lawn-tractors.html
And this: https://www.tractordata.com/lawn-tractors/tractor-brands/rugg/rugg-lawn-tractors-year-sorted.htmlExpert Moron Extraordinaire
You're just jealous 'cause the voices don't talk to you! -
Not only dimensions be the same, but the resistance as well.
Also if your spark plug wire/boot is old it could be reading a higher resistance, diminishing spark/ignition.Don't take experimental gene therapies from known eugenicists. -
Briggs. The mower brand is Rugg with no identifying plates. Engine just has generic info on it.
In addition to the manufacturer = Briggs and Stratton, there has to be a Model No. and Serial No. somewhere. The newer ones have Model, Type, and Engine Code. Don't know about the old ones. They may have changed their system after 1965 (of course lol)
https://www.briggsandstratton.com/na/en_us/support/faqs/browse/engine-codes-model-numbers.html
https://www.briggsandstratton.com/na/en_us/support/need-help/push-mower-engines.html
https://www.briggsandstratton.com/content/dam/briggsandstratton/na/en_us/Files/Numerical_Designation_System.pdf
Engine Date Codes for 1965 and earlier used a different system:
https://www.briggsandstratton.com/content/dam/briggsandstratton/na/en_us/Files/FAQs/BriggsStratton_Antique-Engine-Manufacturing-Dates.pdfPost edited by Gardenstater onGeorge / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
No model, type, engine codes? After B&S down-sized, the employees must have relocated to Gallagher Mansion.Don't take experimental gene therapies from known eugenicists.
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And it turns out (wow) you can download antique engine manuals:
https://www.briggsandstratton.com/na/en_us/support/faqs/browse/antique-engine-specifications.htmlGeorge / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
FYI, the Champion RJ19LM is just a hotter version of the RJ17LM that I showed above. Various small engine talk seems to recommend the hotter one for cold climate or snow blowers. In think the 17 version is probably what you want.
