Autolite 3116 Sparkplugs

Dave F. · Aug 28, 2017

I've been very please with Autolite spark plugs, In using them in my other tractors, ( Ford, Case, IH) but notice the 3116 fouling on my John Deere H. I would Like to know if their is a hotter Autolite plug? I hate to mess with my carburetor adjustment it runs well & fairly easy to start. Thanks Dave F.

mnoliverguy · Aug 28, 2017

Try AC commercial plugs they worked in my B and did not foul

FBH44 · Aug 29, 2017

Some years ago Autolite sent me a spark plug catalog. Here's my notes on hot and hotter plugs. I believe the 388 is hotter.
2014 Autolite Spark Plug catalog
Heat Range Chart page 4-5

18MM thread size 1/2? reach 7/8? hex
HOT rating
388 Standard resistor plug
3116 ?Power-Tip? Non-Resistor plug
386 Standard resistor plug
[gap]
[gap]
373 Standard Non-Resistor plug
COLD rating

Each step up equals a 70? ? 120? increase in spark plug tip temperature.
Self-cleaning zone is 500?C to 850?C tip temperature.
IF TOO HOT = Possible severe engine damage, pre-ignition, detonation with
racing / high performance engines. .
IF TOO COLD = Possible fouling, possible mis-firing, but no engine damage.

John T · Aug 29, 2017

While the 388 is a tad hotter I believe its a resistor plug while the 3116 is not and I prefer non resistor plugs and wires ESPECIALLY if its a magneto ignition. It can help reduce fouling if you use radiator curtains or shutters or t stats to get and keep the temp up to and over 170 degrees,,,,,,,,run the carb as lean as possible,,,,,,,,insure carb float level is correct,,,,,,,,,,,,insure no restrictions in air inlet piping or air cleaner system,,,,,,,,,insure choke butterfly pate is opening fully,,,,,,,,,keep ignition well tuned with good clean points CHECK THE POINTS !!!!!!!!!!!

John T

Cockbird_Hunter · Aug 29, 2017

Try Pat Browning's choice plug for the H, the Denso L14-U.

buickanddeere · Aug 29, 2017

If a 3116 fouls it is not the fault of the plug. You can't blame the plug when the coolant temperature is too low, the mixture too rich, putting around driving instead of working and a high ash motor oil making fouling worse if she is Burning oil.

Dave F. · Aug 29, 2017

My H doesn't burn oil. has magneto & has good / new points. I'll try closing the shutters & get the temperature up more, mnoliverguy tell me more about the A.C. commercial sparkplugs & where to get them? Thanks Dave F.

buickanddeere · Aug 29, 2017

195F or higher and run both the carb's idle and main slightly lean instead of slightly rich.

RandyB(MI) · Aug 29, 2017

Buick, I've been trying to tell people this when they are posting this same Q on JD FB page whenever they get into this arguement. Won't listen. When you use something in ways other than intended use , you must make sacrifices . They were designed to work , and at 170 or higher. If one is going to "putter" then take them out once in a while and burn them clean again and they work just fine. I agree with you and the poster above, if you are fouling a 3116 then it isn't the plugs fault. See, even we can agree once in a while LOL

John T · Aug 30, 2017

Looks like for once lol most of us all agree.........Get the temperature up,,,,,,,Run the carb on the lean side as much as possible,,,,,,,,,,,Keep it well tuned and use NON Resistor plugs (such as 3116 or equivalent) and wire core wires since its a Magneto. Low temps and rich mixtures and/or oil burning will foul ANY BRAND of plug.

John T

Autolite 3116 Sparkplugs

Dave F.

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mnoliverguy

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FBH44

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John T

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Cockbird_Hunter

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buickanddeere

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Dave F.

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buickanddeere

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RandyB(MI)

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John T

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