Best plug .... Autolite 388 or 3116 ???

Crazy Horse · Oct 8, 2012

Continuing on with my questions on plug fouling for my Farmall A, lots of good advice so far. I'm getting plug fouling (oil) using Autolite 386's which are the standard plug recommended it seems for the model A. I can get either 388's or 3116's from the local NAPA store. First, I have a magneto ignition system. It seems the 386's are the hottest of the two choices but they are resistor (or noise suppression) plugs and apparently not recommended for magneto ignitions according to stuff I've read on the internet. The 3116's are non-resistor plugs (recommended for mags apparently) but are not quite as hot. They lie somewhere between the 386 and the 388 series heat ranges. Any comments on which way you'd to if you had to choose? The tractor is not regularly driven and when it is, not used for long extended periods of time.

Jason S. · Oct 8, 2012

Well...I may be wrong or get blasted but magneto"s and resistor plugs are a big no no...the 3116 is non resistor but if I remember right it is more of a projected tip like the champion D18Y. I do know they crossover to each other. I run champion D21 in my A and have no problems. Usually a projected tip will foul easier.Do you have copper core wires? That makes a big difference. If you want an equivalent to the 386 you can run AC C88L if you want to try a different brand. Or try the D21 champions which is a step hotter.

MisterT · Oct 8, 2012

(quoted from post at 19:55:23 10/08/12) Continuing on with my questions on plug fouling for my Farmall A, lots of good advice so far. I'm getting plug fouling (oil) using Autolite 386's which are the standard plug recommended it seems for the model A. I can get either 388's or 3116's from the local NAPA store. First, I have a magneto ignition system. It seems the 386's are the hottest of the two choices but they are resistor (or noise suppression) plugs and apparently not recommended for magneto ignitions according to stuff I've read on the internet. The 3116's are non-resistor plugs (recommended for mags apparently) but are not quite as hot. They lie somewhere between the 386 and the 388 series heat ranges. Any comments on which way you'd to if you had to choose? The tractor is not regularly driven and when it is, not used for long extended periods of time.

If it uses a magneto, it really needs the non-resistor 3116s.

John T · Oct 8, 2012

Fer as I know the 388 is hotter then the 386 and the NON Resistor 3116 is somewhere in between those two heat ranges. Its really best to use a NON resistor plug with a Mag ignition so looks like youre stuck with the 3116 but Ive had good luck with them

John T

Paul from MI · Oct 8, 2012

I just put a set of 3116's in my Farmall H. It had C43 AC's, but they were a bit cold and fouled easy, contributing to rough running. I've had the best performance with 3116 Autolites in my John
Deeres, and they have magnetos and run very cold in the winter.

randy hall · Oct 8, 2012

our gas tractorrs all get 3116's. and we have a bunch of them.

gene bender · Oct 9, 2012

Maybe the problem isnt plugs . Take a compression test after adjusting tappets. Get new wires. Are all plugs fouling or just one or so. Remove them and lay them in order where they go this can tell you some more info. C87 ACs will work along with Champion D-21.

glennster · Oct 9, 2012

its a band aid fix, but you can put anti fouling caps on the spark plugs. they screw on the end of the spark plugs and hold them out of the combustion chamber. napa has them. used for high oil consumption engines.

Harold H · Oct 9, 2012

I don't have the plug numbers and heat ranges available, but, do not use resistor type plugs with a magneto system.

Harold H

Dougct · Oct 9, 2012

I used 388's in my farmall c before i rebuilt it.They worked great,the 86's would foul.

Best plug .... Autolite 388 or 3116 ???

Crazy Horse

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Jason S.

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MisterT

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John T

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Paul from MI

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randy hall

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gene bender

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glennster

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Harold H

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Dougct

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