Old dog DID NOT learn any new tricks!! LOL

Well I am just about to admit to surrender on this darn JD 4020 gas. I have been using it this week. Nothing heavy just general barn yard type of stuff. It has been running great. Kind of nice to use.

So this morning I needed to go over to an out of town land lords place and do some bush hogging for him. So I decided to take the JD 4020 gas as it also has a loader on it and some times there is brush that needs shoved out of the way. We worked all morning and it ran great. Took throttle and ran smooth. At lunch time the landlord's wife had some sandwiches made for us. So I shut the tractor off to eat lunch and I also wanted to adjust the clutch free travel as it was a little too tight. Went to restart the tractor and it just about did not start. Just about cranked the batteries dead before it started. As soon as it did start it was missing. You had to give it throttle real slow or it would start to stumble and backfire. I tried to identify if it was one cylinder missing. It is not. The plugs are not black with carbon, they are white. I fooled with it for a short while and finally had him run me home. I loaded up the JD 6400 on the trailer and went an finished the mowing for him.

After I was all done and had hauled the JD 6400 home, the JD 4020 gas started right up when I went to load it on the trailer. It misses bad enough it will not pull itself in road gear. I let it run while I hauled it home. When I got home it was running a little better and would take throttle but it still has a random miss fire. I fooled with it for an hour or two this evening. I am pretty sure it is an ignition problem. I am leaning towards a bad coil. It has been switched over to an electronic system. It has one of those yellow coils on it. Do any of you know if I have to use the electronic ignition manufacture's coil??? can I just use a regular coil?? The reason I am asking I do not want to harm the electronic system with the wrong coil but I am not sure that the coil is the trouble. It is missing under load when trying to increase RPMs. Everything else check out. Plugs are good, wires are good, tried another known good distributor cap, Compression test and leak down test both show the motor as being good. So it just about has to be the coil or the trigger assembly.

If any of you have a better idea I am very open to subjections on this thing.

P.S. Checked the valve setting last week before tearing into the carburetor.

This will cause everyone to come unglued, but...

I don't trust those EFI setups. Some guys have great luck with them and some can't get it to work for anything.

I had an old car once that I bought for my mom. I tuned it up and was running it for a week. It started to act just like that tractor. Just like it. I popped the original rotor back in the distributor and it was back to its old self. I'm not sure what happened with that cheap rotor, but it went south on me. Swap the rotor.

Take a close look at the rotor. We had a puller that wouldn't run either even with a new cap and rotor. After switching out for another new set it came to life again.

I've seen some electronic kits that specified their coil, but I think maybe they were just trying to sell coils or were wanting to make sure the right resistance coil was used for warranty protection and proper performance.

The conversion kit is nothing but an electronic switch, so I see no reason a regular coil in the 3 ohm range wouldn't work.

Have you tried connecting a volt meter to the ignition side of the coil, running it until it fails? Could be high resistance through the switch, a bad connection lowering the voltage intermittently.

Steve I checked the voltage to the coil with a digital volt/ohm meter and it is correct. I even took a jumper wire and ran it hot from the battery just to see if it made any difference. No change

I'll take it off your hands ! Bring it on over.

Even though you say they look OK, I'd change the plugs before I did anything else. I say this because they haven't been run 'bad' long enough to really show an issue in their color. As such, one could still have a break down, internally, of the electrode, and just isn't firing like it should, causing the miss.

Mike if the darn gas engine keeps giving me issues I will put a diesel in it. I already have one lined up.

IMHO, over the long haul, quality breaker points and an OEM coil or equivalent will cause a LOT less problems than aftermarket EI with a "hot" coil.

I've had "Ingrid" for quite a few years and have yet to change the points and she has always started (reasonably) well with ZERO ignition problems.

You remind me of the song, Your the reason God made Oklahoma! In the lyrics it goes , I worked 10 hours on a John Deere tractor.... But it never mentions if he ever got it going! LOL

The Holley distributor in my Oliver 1550 gas made the tractor act something like that before I replaced it.Also have had Autolite distributors in Cockshutts do the same thing.

JD Seller:

If you have Carbon center plug wires they will test out OK with a meter but will break down due to heat while in operation, especially if the machine is being worked hard. I've had that happen a couple of times on different pieces of equipment; drives you nuts trying to figure out what the problem is, and it turns out to be nothing more than a plug wire or two that are failing under load.

HTH

Doc

The stumbling and backfiring when you try to give it throttle sounds like a spark advance problem. Have you checked the centrifugal advance weights in the distributor for free movement? Maybe it wouldn't start because the timing was too far advanced. I had a truck once that drove me crazy until I figured out the weights were stiff and sticking in different positions throwing off the timing.

I've noticed in CL, there is just about always a JD4020 for sale. While large in hp, they sound like a dandy haying tractor. Nimble, parts everywhere and most rebuildable. Prices are IMHO good too. Sounds like the 4020 is one of your favorites. Some of the 4020's are gas (along with 3020's) and the price is typically lower than a diesel. So I'm reading about the "gas" 4020's and 3020's.

What I've read on these gassers does not give me a warm and fuzzy. Over in the IH section, I inquired about the gas IH later models, like the 756, etc and what I glean from the replies and from general searching/reading, is - is they are a dependable/good gas engine.

I'm watching your efforts on the 4020 as, like I mentioned above, they would make a good haying tractor - and there are some deals on gas versions of them.

Good luck,
Bill

JD, I am right there with you on your gas tractor. I have a 1650 that is driving me bonkers. I have done exactly what your are going thru. Yesterday I picked up the carb from a retired machinist that comes highly recommended. He didn't find anything wrong, but I wanted to have confirmation. I recently replaced the electronic ignition. Had some heifers chew the wires while I was eating lunch. I knew better than leave it, but was in a hurry. Anyway, it made no difference. But the warranty mentioned to only use non resistance coil. I looked and it was a internal resistance. Changed, nothing. I replaced all the rest of the ignition. checked the valves. Nothing so far. My next and last that I can think of thing to do is pull the manifold. Good luck, I hope you find your gremlin.

with electronic system use carbon core spark plug wires or sooner or later it will cause a problem

When you buy a 4020 gas or diesel but especially gasser you've just made the down payment as both are fuel hogs.

Hard on fuel compared to what? What tractor that size and age is much better on fuel than the 4020.If you want to own the Cadillac of tractors you can not expect the fuel economy of a voltswagon. I am not a fan of the 4020 gas and like to say that every time I start mine somewhere in the world an Arab gets a smile on his face. Tom

Had the same thing with a 830 Case gas. Would run fine for a while then not. Got another new rotor and ran fine. After warn-up it would short thru the bakelite material of the rotor to the dist. shaft.

I think you have way more important stuff to worry about, so I can come get it and the diesel motor to relieve the stress load. Just looking out for you LOL I have no good advice for you other than put the diesel in and forget about it. Happy 4th

When I ordered the Pertronix electronic ignition for my Oliver 1550,I did it by phone. I asked the guy if it was necessary to change to a hotter coil. He said no,not it you're just using it for general use,so it still has the original coil on it that it had with the points system. I don't know how long it's been since I changed it over. I'd have to say ten years or more.

I think it is that electronic ignition. I have had cars with that and that is exactly the way they acted. Had to replace it. Had 2 cars with that and it was so bad we always carried a spare unit with us that we could change out on the road. I would put it back to orignal from factory.

Just to eliminate the electronic ignition put in a set of points. They're cheap and will keep you from guessing. Go back to the EI when you eliminate it and you get the engine running again.

Mornin JD, Happy Fouth of July Hey were never too old to learn right?

I will answer your questions but NOT open a can of worms ad get into the whole EI versus original debate as thats NOT your question.

QUESTION

1) It has one of those yellow coils on it.

Some of those are after market high energy high voltage coils that draw "might" more then the 4 amps points handle well but "most" (subject to switch current rating) elec switches can handle no problem. The ability to use a high voltage high energy coil (draws more current then stock coil) is one reason the EI is used in first place plus many gents then run a wider spark plug gap yielding a higher energy (volts x amps x time) high heat arc producing discharge over a wider plug gap distance to ignite the fuel.

2) QUESTION

Do any of you know if I have to use the electronic ignition manufacture's coil???

NO you could use the stock coil as the elec switch "probably" no warranty however, has plenty of current capacity

3) QUESTION

"can I just use a regular coil??" YES see above

HERES THE DEAL an elec switch mfgr bases his coil recommendations on the switches current switching and carrying capacity SOOOOOOOOO he sure wouldnt recommend a coil that draws too much current for the switch to handle WELL DUH and while the switch can handle the current most stock coils draw THAT WONT YIELD YOU THE MOST BANG FOR THE BUCK AN ELEC SYSTEM HAS TO OFFER so they will prob recommend a matched high energy high voltge coil the switch can handle so you end up with a higher energy ignition and you will be happier with improved performance. NOTE the firing voltage depends on the plug gap and medium (compression and fuel) so an HV coil wont fire any higher then a stock, its just that a HV coil has the CAPACITY to achieve higher voltage if required, but thats harder on wires and caps n rotors !!!!!!!!!!!!

SOOOOOOOOOO while you can use the stock coil (give a stock coil a try to see if your "yellow" coil is bad), the EI mfgr may recommend a high energy high voltage (as needed to fire a spark across a wider gap) BUT REST ASSURED IT WILL BE ONE THAT MATCHES THE SWITCH so its current isnt exceeeded.


QUESTION

The reason I am asking I do not want to harm the electronic system with the wrong coil but I am not sure that the coil is the trouble.

GOOD THINKING if you used a coil that draws more current then the elec switch can handle POOF but "many" elec switches can handle "many" of the higher energy after market coils THATS WHY YOU SHOULD USE A COIL THE MFGR RECOMMENDS AND NOTTTTTTTTTTTT someone here (including me) DOES.

CLOSING THOUGHTS AND ANALYSIS

A) PLUG WIRES: Often an EI user will run a wider plug gap which increases firing voltage so you need good quality HV rated plug wires, be they resistive suppressor carbon core or wire core. HOWEVER I believe some of those switches which use a HV coil with wider plug gaps may prefer a certain degree of IMPEDANCE in the plug wires and may use spiral wound plug wires and if the selected switch and coil is best with those specific plug wires THEN USE THEM. Carbon core suppressor plug wires reduce radio interference as opposed to straight wire core, but the Elec switch has plenty of energy to spare so if regular carbon core (NOT spiral wound wire) wires are used thats genarally not a problem nor are wire core UNLESS the whole system works best with spiral wound.

B) COIL generally speaking the coil is NOT my first suspect when there are ignition problems, usually its the points or condensor (in old systems) or the spark plugs or plug wires or cap n rotor and that "yellow coil" MSD or ACCEL??? is prob as good or better quality then the stock.

C) ARE YOU RUNNING A WIDER THEN STOCK PLUG GAP (say 0.035 to 0.060 even) ??????????????????? If so thats a strain on stock cap n rotor n plug wires so Id be looking for HV breakdown evidence or carbon traces or hairline cracks in the cap and Ive seens rotor tips suffer HV breakdown when running wide plug gaps and HV coils etc. Try to find a real dark place tonight and ruin her and see if theres any arcing going on???????????

D) FINAL THOUGHTS Sure an elec switch can fail and I cant tell if thats your problem or not. I would however FIRST suspect plugs or plug wires or cap n rotor or spark advance mechanical issues and then perhaps the coil or switch itself. Does the plate upon which the magnetic rotor assembly (where points used to mount) feel smooth n even and rotate back n forth????????????????????? YOU COULD HAVE A MECHANICAL ADVANCE ISSUE...........OR BADLY WORN BUSHINGS AND BEARINGS IN THE DISTRIBUTOR.............. TRY HER WITH ANOTHER STOCK COIL AND SEE WHAT HAPPENS as most elec switches have far more capacity then a typical stock coil draws but I wouldnt hang on just any high energy HV coil like an MSD or Accel etc that may exceed the elec switches capacity. Is the air gap between the magnetic rotor and pickup coil in the distributor correct and all well attached??? Probably is and is fixed mounted but I cant say from here.

Youre a good hand to help folks with general and farming questions where youre experienced, so its fun to help you in return in areas where I have at least some degree of expertise. I tried to educate you on the hazards of electrocution (per OSHA and the NEC) driving an earth ground rod might cause when using portable gensets wired and configured in certain ways, and now hopefully help you understand the basics of elec ignitions, youre a good teacher as well as a good student.

Happy Fourth of July and God Bless you and God Bless the USA

John T Tooooooooo long retired Electrical Engineer and rusty on all this SO NO WARRANTY I may be wrong as rain!!!

Try buying gas for a 1800 Oliver

I have a friend that had a similar problem on a 66 mustang. He went through everything and couldn't find the source of a miss. The dead giveaway was that it had low vacuum. An old mechanic suggested it might have a crack in one of the intake manifold runners, he put a different intake manifold on it and it runs perfect. I have a farmall 300 with a pertronics kit on it, it idles rough but always runs well off idle and starts instantly. I have several classic cars and I'm reluctant to change them to electronic because if they quit on me I can get points anywhere.

Bring it over, I will help you inject it

Do you have facts to back that up?

Our 4020 Diesel is pretty stingy on fuel.

You will feel real good once you solve the problem, whatever it is. Sounds electrical, but just don't change a whole bunch at a time. Change one thing at a time until it runs better and you will have found the problem. I had a Ford van once that developed a problem like that. I left it at a repair shop for 2 days and they couldn't find the problem. We wanted the van for a weekend trip, so Friday night I went to K-mart and I bought a new set of plug wires. Put on the new wires and it ran like a charm! It's just a matter of finding the part that is failing at some interval.

My landlord has a 3020 gas I switched it to electronic ignition 8-10 yrs. ago. Have not fouled a spark plug since. I can't believe it is the same tractor. If I remember correctly the coil and electronic ignition came as a kit. Changed it from positive ground to negative. Now is enjoyable to use. I don't know how they ever sold any gas ones they way it ran before. Hope this helps.

Dad had a 4020G. A bad condenser left him stranded shelling corn at a neighbor's place. It ran well, they took a break and it wouldn't start. He let it cool down and it still wouldn't start cold. Replaced the condenser and it ran great again.

I realize your tractor has an electronic ignition, so no condenser. The electronic conversion might have been installed in an effort to "fix" a bad distributor. A timing light would help diagnose that.

Bush hogging is hard work on most tractors....sounds like it was hot when you shut it down, (could be why it was hard to start) and drained the battery trying to start it, to the point it would not run right?
Maybe the battery is not charging? Just a thought.

Keith

In the mid-1960's Deere sold a fairly high percentage of 4020 gas tractors compared to other brands with tractors that size. The 4020 gas were priced close to a 3020 diesel, so many livestock farmers went with the bigger gas tractor. For machines that didn't run a lot of hours a year it was economical. In the 1960's most combines also had gas engines.

I had trouble with a 610 Bobcat that I'd switched to EI. It has a 4 cyl Wisconsin in it. It would run until shortly after the warranty ran out then lose power, start missing then die at the most inopportune moment. I changed the EI module twice then went back to the point setup, I kept them, they last a couple of years. It's alot less expensive with the points.

White plugs are lean. They should be a light brown.

I don't think I've seen an electronic unit that wouldn't fire a regular coil. That includes MSD units.

The fancy coils are supposed to fire at higher voltages if the conditions need it.

RT (my2?)

I converted my 64 model 4020 to electronic ignition going on 25 years ago. I used Chrysler EI system because it is a good system I am very familiar with and all the local parts houses have all parts for it(coil, module, dual ballast resistor . It would have been easier to buy a Pertronix unit, but while those I have installed, have worked well, I don't like that no one local stocks Pertronix modules, as the module is 95% of the cost of a complete kit.
The Chrysler setup has been very reliable, near 25 years untouched. This summer the 4020 began to start harder and ran a bit rough at low rpm, very rough to the point of being unusable at high rpm.
Troubleshooting proved the problem was a weak coil. I replaced it with another used Chrysler coil and all is well again.
You don't have to use the EI builders coil as long as you replace it with one of the same primary impedance, usually 1.5 ohm with a ballast resistor, 3 ohm if 12V without a ballast resistor.

One big problem I had with the 64 4020 gasser was that the ballast resistor built on the rear of the ign switch was weak from new,(only supplies 4-5 volts to the coil, which degrades even more with 2-3 years use on the switch. Easy on points,yes, but causes the chronic weak spark / hard starting / bad running / plug fouling problems those engines are known for.
I wired in a 30 amp cube relay to supply power to the ignition system directly from the battery through short 12ga wires, so ignition is much stronger than stock. The original ign switch, resistor and wiring is only used to close the cube relay to power the ignition.
With this hot ign system, starting / running is so much better than stock, that it along with the smaller U Moline carb, totally changes the character of those tractors. They run and pull with the enthusiasm of the diesel models. Those gas tractors lack mostly in 3 departments that are quite easily fixed,1 the weak cranking is fixed by replacing the far too small Delco MT10 starter with a much stronger MT25. 2 replace the weak stock ignition and ballast resistor system with a much stronger and reliable electronic ignition.3 Replace that nasty troubled oversize carb with the smaller U Moline unit.
You now have a tractor that cranks so fast that it has to slow down to idle, It starts and runs without spitting / missing and a set of plugs work reliable for 10+ years without fouling.
Replacing that oversize carb with it's troublesome accelerator pump, gives you a tractor that pulls strong from idle through mid rpm with great torque ,and still makes good power at full speed. BTDT , hated the tractor before, love it after the mods.

THAT is the best suggestion on this thread! Of course I'm not the one bankrolling it lol