Different Running John Deeres

Roger46

Member
I was at the Threshing Show in Almelund, MN this weekend and noticed (as I have noticed before at other shows) that some of the older 2 cylinder John Deere's seem to run differently than other ones. I have a 1949 B that I have totally restored and it runs smooth, but some of those older models seem to run with a gallop. They almost sound like a version of the hit and miss engines but not quite. Is it just the way they have the carburetor set or not tuned up right?
 
I've also noticed the same thing. Anybody can shine one up to make it look good. It takes someone that knows what they're doing to make it run good. Or possibly they don't know how they're supposed to run. Either way, it bothers me to see such nice machines run so poorly.
 
JD cams were not real good until the later 47 As came out. The grinds were much improved and lobe separation was much better which lead to a lot better idle, better power along with other changes to the engine.
 
I thought I heard once that the early JD's ran irregular when not under load because the carburetor didn't feed both cylinders the same, but when under load they were fine. They were built for working, not parading! I would like to go to the
Almelund show sometime, I have a shingle that my parents got there 30 years ago.
 
When right and tight an old '30,s JD will idle perfectly smooth and even. Could be many reasons but usually carb is not built or built correctly. "They never run evenly" is an old "farmers" tale stemming from the fact that as long as they worked under load fine, no one spent the money to build he carbs and make them idle right.
 
Restricted idle passages, worn throttle plates and bushings, leaking intake gaskets and the list goes on and on. Fix them up and they run like a sewing machine but the reason these old tractors run this way is mainly that they can. Most farmers didn't fix things until they broke but old two bangers could suffer from various issues and still keep on working.
 
ndbjda you realy don,t know would you are talking about the change came at serial 620xxx and that is mid 1949 production. that change was a larger brg and housing on the gear end of the cam
 
You need to stop and chat with the owners a few minutes for the correct answer. A lot of folks will drop the idle speed way down so they can hear each cylinder firing and that gives it the different sound you're hearing. They are quite proud it will drop that low and still keep running. Don't bother telling them they are destroying their bearings cause as long as they get that sound they don't care. Contrary to what you've been told there is absolutely nothing wrong. They are very carefully set that way on purpose just because they can and nobody else can.
 
Every tractor can vary from a similar model in the way they run sometimes.
Now you go back to the early ones they are the most noticeable in running more roughly I think. I had a 1927 D and noticed that.
I have noticed differences in how one runs with swapping carbs. too.
And then many times just some fine tuning of the adjustments can work wonders on them.
 

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