JD Occasional Miss

forty40 · Jul 17, 2022

For the big cu-in JD s my observation has been that they are susceptible to an occasional miss which is actually a "cough" back through the intake, usually under moderate to heavy loads. My A is 644, not huge by today s standard, will occasionally cough right near the end of a hook. A couple weeks ago, two big G s pulled one right after the other. One coughed every 50 down the track, the next G didn t cough once. Haven t noticed it in the stock classes. Some tractors do it all the time, some during an occasional hook, and some never miss a beat. None of them are poorly built or cheap tractors, I would like to know if there could be a common cause. One of my friends tractors ran perfect, changed cranks due to time on old crank, and it s not been the same. These pullers aren t beginners or new to JD, but some have a stutter and some do not. Often with the same ignition parts and carburetor.

MSD · Jul 17, 2022

I've found on mine if I run to slow of a gear and it doesn't come under load right away that it will skip a beat. Going up a gear or riding the breaks to get it down the
track aways helps. A cough at the end of the track is a sign that it is running out of fuel. We have come up with a fuel bowl system to eliminate that. It uses two
needle and seats and floats so you can run higher fuel pressure and it increase the size of the fuel bowl. Guys that have put them on say they make a noticeable
difference.

JD Occasional Miss

forty40

Member

MSD

Well-known Member

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