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Year

Champion Spark Plugs

grima Are L77JC4 & QL77JC4 the correct Champion spark plugs for a Johnson 115 (1970 model)?

If so, what's the difference between them?

2002-02-20
Dhadley Yes. "Q" denotes a suppressor type plug.

Good luck!

2002-02-20
EatMoreFish Champion spark plugs
Back in my airboat days, I had a 0470 continental aircraft motor (220 hp 470 ci 6 cylinder). After putting in dome pistons in it (maybe a few other things), every time I would open it up it would blow the porcelain right out of the Champion spark plugs. Other types seemed fine (ie AC) but the Champion spark plugs seemed weak so now I never use them in anything. But at that point we were not talking pump gas anymore also.
Just my 2 cents
2002-02-20
Capn Mike Hmmm....I was just going to post a question about Champion spark plugs. I have a 200 hp Johnson, which came with Champions, but have been told by several people, that NKG are far superior. Bought 6, will put them in this weekend. Had an auto parts guy tell me Bosch were just as good.
Anyone had any experience to chat about?
2002-02-20
Dhadley We have done a lot of testing and research along these lines through the years and can tell you this -- stick with Champions in an OMC (carb) motor.

Good luck!

2002-02-20
Trent Crawford Eatmorefish...Were you using aviation sparkplugs?? Iv never seen one do that in over twenty-five years. Use Champion plugs everyday in aircraft (They are the #1 maker of aircraft plugs and oil filters). 2002-02-20
Capn Mike Dhadley, mind telling me a little more about who "we" is? Repair shop, dealer, or some such? Thanks! 2002-02-20
EatMoreFish I forget the exact plug .. I will look tonight and see if I can find one
On the airboats we would remove the aircraft wires ect and use racing type auto ones it was cheaper. We had compression so high that sometimes it would diesel on the better fuels. We would do all kinds of things that you would not on a plane
Cutting the rockers and rewelding them
Nitro
putting them on 10' boat with basa (sp?) wood stringers and so thin you could see through it with a lighter
Racing 1/8 mile +- on the top of dikes at Kissimmie
spent more time on dry land than my truck did
Spinning those big props till they screamed. Tried to keep it under 3200 (that is screaming for aircraft) but somedays it went beyond that. I know one go that was *****ing about losing the tips on his props. He was spining them at 4800 +- I would hide when he ran his boat
2002-02-20
EatMoreFish Franky guys on a stock motor it should not matter 2002-02-20
Dhadley Mike -
I ran the outboard remanufacturing division of a marine engine company for 20 years and we did all sorts of independent testing for other companies. I now have my own company and do testing and consulting for several manufacturers. One of them manufacturers pistons and they are particulary interested in the relationship between spark plugs (correct and incorrect), todays fuel and pistons. It's an ongoing learning experience.

Let us know how you make out. Good luck!

2002-02-20
almost retired again For what it's worth I worked most of one day chasing my tail on a Johnson 200. It had a brand new set of NGK's so I ASS-U-MEd that couldn't possibly be the problem with an engine that it wouldn't even attempt to get on plane. I tried everthing even changing all ignition parts with new the sympthon still kept pointing to the plugs, so finaly I changed those brand new NGK's. walla problem solved. After changing back all those new parts you can bet that I've always used what the factory recommended. What it turned out was those NGK's put out so much RF noise that it was interfering with the pack.
That's my horrow story; take for what it's worth
2002-02-20
djohns19 It has been my experience that Champion makes a decent "general" plug. They make them for everything. Whether or not they're the best fit for every machine on the planet is another story.

I agrtee with dhadley, if the engine came with them ,stick with them. Otherwise, use what the engine came with. Imports seem the most sensative to this, whether they be marine engines or automotive applications.

2002-02-20
Dhadley Absolutely Djohns19 -- to expand a little further on what we found, I wouldn't dream of recommending a Champion plug for some engine that was meant to use something else. The Merc / Yamaha / NGK combination comes to mind.

I must also point out we are talking about stock recreational motors. We have indeed used NGK plugs in an OMC but it was a race motor dumping tremoundous amounts of fuel and turning 9000+ RPM. A far cry from stock. Ah, the good ol days!

Good luck!

2002-02-20
Boo Almost retired again,
Could you explain to me why the NKG's cause
this RF noise to the pack(s) and are they the only plug that can do this to a outboard motor? what exactly is RF noise? Thanks
2002-02-20
jegervais ANY non-suppressor spark plug can "cause" RFI. The plugs don't actually cause the RFI, the ignition coil does. Almost all of the OMC-built cd-ignition systems require a "Q" style Champion plug, Q designates Suppressor-Resistor. The NGK plugs, although the 2002-02-20
Boo Hey John,
Thanks for the information, it's greatly appreciated.
2002-02-20
G DANE Thanks Dhadley and John for this very special information.

I experiendes champion spark plugs last longer than NGK i smaller crossflow motors, probably realted to their better function.

2002-02-21
almost retired again Hi Boo
John from Illinois pretty well answered your question about radio frequency interferance (or noise).I personally think it was activiting the SCRs (silicone control rectifiers) in the power pack cousing the engine to basicaly fire when ever it wanted to, or whenever they got a spike of rf voltage.
2002-02-21
petryshyn Hi gents

The whole idea behind resistor plugs is to add resistance into the secondary (high voltage) circuit. This increase in resistance reduces current flow through the coil secondary winding, plug, and wire. The reduction in current results in less m

2002-02-21
PeeWee Dhadley,In no way am I saying your wrong,the only plug I have good luck with, is Bosh. I run them in everything.I have never had good results with champion,(not since the mid 70's).I live in south Texas, could it be the heat? 2002-02-21
Trent Crawford I hate it when I Learn somthing NEW! Thanks Schematic and Mr. Gervis (John). 2002-02-21
seahorse5 Find a back issue of Bass and Walleye Boats magazine for a complete explanation of suppressor verses resistor plugs, and how they work. It is the April 2000 issue and the story is titled "Firing Line". 2002-02-22
rwise Helo all!
I have ran NGK in the dirt bikes I rode, great plug for that! I run champion in every thing else, no problems ever! Bosh, I tried bosh in my '49 ply, would not start! Picked up the champion plug from the ground, put them back in. Popped off first time! I have never tried Bosh again! In anaything!

Just my $.02

Richard

2002-02-22
petryshyn Hey seahorse5, are those older issues of Bass and Walleye Boats available online anywhere? I'd love to read some of their articles. 2002-02-22
Capn Mike I'm back! Finally got around to installing the NKG plugs (used their cross reference to the Champions that came as OEM; they are resistor plugs, with a big R below the brand name). Ran the boat for a time yesterday, will go fishing this weekend and give them more time.
From what I could tell, I didn't get any more or less performance than if I installed new Champions. We'll see what time tells. In the meantime, the engine and all the radios work.....
2002-03-15
novacane blowing out the porcein is usely caused by detention (ping) two flame fronts coliding
seen this often when fuel octanes whent down, to hot of plug to hi compression or a tad to much ign lead humm just a tought
before cooper was interduced in the champion
center eletrode thay where real unstable in the heat range deptment just a thought from back yard harry
2002-03-15

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