[AT] Spark plugs

[deanvp at att.net]

Autolite 3076 is about as hot as you are going to be able to find unless you
find some obsolete Autolite 3077's. The last digit on the Autolite plug
number gives it's heat range reference.  If you do a cross reference on the
Autolite 3077 some other plugs will show up such as AC Delco 18 and 18A and
a couple Champions W890 and Champion Stk 589.  I don't know if they are
commercially available and fit properly. I have no experience with those
spark plugs other than the Champion brand plugs have never worked well in
any of my old tractors. I run 3076's quite a bit in my JD letter series
tractors and only one tractor  I have fouling problems with them. On the 35
JD B. I also have trouble getting it to run hot enough, over 200 degrees,
even with the curtain all the way down so I use cardboard over the radiator
as well. That reduces the fouling and I also turn the load needle in a 1/2
turn or more when not under any kind of real load such as when I'm parading.
That leans down the carb and reduces the fouling as well. Try looking for
the sweet spot as to how far you can lean it out when not really working the
tractor much. That will be your best solution. The tractor will tell you
when you have gone too far or if you truly load it.

 As a side note I think I may be fighting other problems as well on the 1935
JD B such as a bad manifold, unequal compression between the two cylinders,
not hot enough spark etc.   But that tractor is in AZ and I'm in WA.  So
this summer in WA I have cleaned up two more carburetors and two more Wico
XH mags to take along to AZ this winter for the process of elimination
testing.  Currently there is a Wico C magneto on it but I m taking down two
Wico XH Magneto's which have a hotter spark than the Wico C.  I just want to
make sure those two components (Carb & Mag) are not the problem.   Then I
can move on to where I think the real problem is.    I hope I am wrong
because problems with compression or the manifold are an absolute bitch to
fix on a tractor this old. 

The G's have a reputation for being as little thirsty for gas so leaning out
your carburetor and running the tractor above 200 degrees should give you
some help until you find a hotter plug. 

PS: When anyone mentions an unstyled JD G I get a flood of sound memories
through my head. We had a neighbor about a 1/2 mile away who farmed a
section (640 acres) of land with two unstyled G's when I was growing up on
the farm.  The sound of those two G's working out in the field was our
"elevator" music on the yard. Even that far away they would come through
loud and clear. It kind of set the tone that everything was ok and normal
for the day. 

Dean VP
Snohomish, WA 98290
"Socialism is a philosophy of failure, the creed of ignorance, and gospel of
envy, its inherent virtue is the equal sharing of misery."
..Winston Churchill...

-----Original Message-----
From: AT <at-bounces at lists.antique-tractor.com> On Behalf Of Gene Derringer
Sent: Sunday, August 16, 2020 6:17 AM
To: AT at lists.antique-tractor.com
Subject: [AT] Spark plugs

I have been using AutoLite 3076 plugs while playing with my 38 G. Does
anyone recommend a little hotter plug to keep from fouling. I have been
reading & learning from you-al, but now I have a question. Thanks for
whatever you can relate.  Gene Derringer, Harrod, Ohio

Sent from my iPhone
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