Spark plugs F20

fixerupper · Nov 20, 2018

What plugs do you guys recommend for an F20 for today's sooty gasoline. It's a late one with overbore aluminum high altitude pistons. It has W18's in it now and two of them cut out after warming up. I just now got it running after overhauling it. Probably hasn't run for 30+ years and these W18's are the plugs that were in it when i bought the tractor. Thanks

16-30 oilpull · Nov 20, 2018

Autolight 3076

Charlie M · Nov 20, 2018

I've got W20's in my W30 and F14. Never had a problem with them using regular grade gas.

robgIN · Nov 20, 2018

Autolite 3076 is what I use in mine with 3 3/4 inch 8000ft high altitude pistons. If you are working it hard and the temp is above 60 degrees out you may need to use higher
octane gas to combat detonation. The carbs run really rich at idle if set for max power, if you are just driving you can lean the carb out if you are having issues with plug
fouling. I have had the best luck with the 3076 as far as not fouling, tried Champions but had a lot of fouling problems.

F-Dean · Nov 20, 2018

If you can find them, Autolite 3077. They look strange but work great!

fixerupper · Nov 20, 2018

I'll find some 3076's for it. These W18's were put in the tractor back in the leaded gas days. I run a hotter plug than what the book lists in my other old gassers and haven't had fouling or detonation problems so far. This is a 39 model, I bought it in memory of a classmate who passed away. The tractor belonged to his dad and the classmate more or less inherited it before he passed on. It had the 3 3/4 8000' altitude aluminum pistons but the pistons had corroded to the cylinder walls and were impossible to get out without some damage. I found another good used identical piston and sleeve set to put back in the block though. The rear rims were widened out to 12" but the tires were so rotten rubber was falling off. Had a lucky break and found a pair of 13.9/36 tires locally to replace them that are in better shape inside and out. Was like finding a needle in a haystack. Whooeee! I don't know what my future plans for this tractor are but I do want it set up so it's dependable.

D beatty · Nov 20, 2018

I have used W18 and if I run on just gasoline I use W14.

CenTex Farmall · Nov 21, 2018

I saw some adapter bushings somewhere that would allow you to run any modern plug you wanted. Not sure if they were for 14mm or
for 3/4" like on an M.

John T · Nov 21, 2018

I much prefer the hotter deep reach side wire electrode Autolite 3077 instead of the cooler standard electrode 3076

John T

fixerupper · Nov 21, 2018

What do you think of 3116 Autolite? According to the Guy at Arnold motors the new number for F20-F30-W30 is 3116. He claimed it's about as hot as you can go.

John T · Nov 21, 2018

3116 is the smaller 18 mm plug and its NON RESISTOR which is my choice for Magneto Ignitions. If I recall correctly its in the middle of the heat range for the resistor plugs 386 and hotter 388. If you have the new style smaller 18 mm or an adapter and a mag ignition ID USE THAT PLUG......If the older 7/8 plugs use the hotter deep reach side wire electrode 3077

John T

fixerupper · Nov 21, 2018

(quoted from post at 10:27:41 11/21/18) 3116 is the smaller 18 mm plug and its NON RESISTOR which is my choice for Magneto Ignitions. If I recall correctly its in the middle of the heat range for the resistor plugs 386 and hotter 388. If you have the new style smaller 18 mm or an adapter and a mag ignition ID USE THAT PLUG......If the older 7/8 plugs use the hotter deep reach side wire electrode 3077

John T

I had a sneaking suspicion the 3166 is the smaller plug. Will call them back.

John M · Nov 21, 2018

The 3077s are no longer being made, so if you find some your lucky. If you want that type youll have to use Champion W89D.

fixerupper · Nov 21, 2018

I got a box of 3076. Thanks all for the advice. Happy Thanksgiving.

Spark plugs F20

fixerupper

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16-30 oilpull

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Charlie M

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robgIN

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F-Dean

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fixerupper

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D beatty

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CenTex Farmall

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John T

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