Hesitation problem

   / Hesitation problem #1  

duke7595

Gold Member
Joined
Jan 22, 2012
Messages
366
Location
S/W MO.
Tractor
820 ,1520,1020 (D) 1020 (G) 1050,4020 2240
i'M RESTORING A 1020 GAS J.D. . I have been working on the mechanics before I start body and paint work. The problem I'm having is hesitation it don't want
to respond when I throttle it up a little fast, it also appears to be loading up when idling. However, it runs well under load but it still has hesitation.

I have changed the plugs ,points,wires and cap but it didn't help. I am not well versed in carb. diagnoses and was wondering if this may be the problem ?
Would appreciate your advice.
 
   / Hesitation problem #2  
Did you change the rotor too? if not I'd change it too- since it directs spark to each plug. You need to verify dwell and timing are correct too if doing a tune-up.
Carb could be problematic, or fuel filter. Have you changed the fuel filter? If not do so.
You could have water in the gas, dirt in the carb bowl, or any number of other things going on. It could be an electrical problem related to the ignition coil, etc. have you done a compression test?
I'd want to get fresh gas, new gas filter, and see what it does then. If no change, then do dwell and timing and compression check.
Report back results.
Could also need a valve adjustment too.
 
   / Hesitation problem
  • Thread Starter
#3  
Coyote machine,

Thanks for the advice, yes I did change the rotor, the carb. does not have a line filter, so I will do as you advised and let yo know what occurs.
I usually deal with diesel tractors and really don't have a lot of experience with gas engines, especially the carb.
 
   / Hesitation problem #4  
duke7595,
I understand your lack of understanding of gas engines, BUT diesels aren't all that different when it comes to fuel, and running overall.
Gas engines of the type your tractor has are infinitely repairable and often at way less than the cost of fixing a diesel with fuel or ignition issues.
Gas being more refined than diesel uses spark to ignite combustion from the plugs, and the rotor cap and wires deliver spark to the plugs. So if properly timed to the valve train, a gas engine will run well with few problems. Clean gas and good spark delivered on time make it go. A good clean air filter is essential too, to keep dirt out of the carb and engine.
Diesels are mostly combustion ignition engines, that use glow plugs, in many instances, to preheat the fuel so when it is compressed it will ignite. The engine just keeps going until someone starves it of fuel. The expensive and highly tuned to close tolerances part of a diesel is the injection pump, which meters the proper amount of atomized fuel in time with the engine's stroke and delivers power to the drive train. When that system goes wrong it can be a nightmare and big $$$.
With no filter inline to the carb the gas will contaminate the carb with dirt, particulate matter and varnish as a result of fuel and how it's processed, how it deteriorates, (think E-10, weasel pi$$), etc. So, before you go tearing apart a carb, check the simpler stuff, and like you did with the ignition circuit, points, cap/rotor, plugs, etc. get some clean, fresh fuel and see what that does for the engine. I'd drain the tank, drop a small amount of fresh gas in it and drain it again, to try to clean any particles/dirt/ rust out of the tank's bottom and then start with new gas. Drain it into a clean container and see what you can see- OUTSIDE, away from ignition sources! If you can I'd add a fuel filter inline by cutting your fuel line and using the proper fuel line and clamps on both sides of the line and both sides of your new filter- BEFORE doing anything downstream at the carb. Make sure the line cuts are clean and not burred, use a knife blade end to CAREFULLY debur each end without letting any cuttings into the line going to the tank or carb.
Then see how she runs- any better? Worse?
After this initial test we can see if your carb needs attention. I suspect it will, but let's do it one step at a time and work toward completion of the fuel delivery system and ignition system, then the metal and other work- which is where I depart to other things and you continue your restoration.
I would take a look at the carb and see if there is a drain screw on the bottom of the bowl which will allow you to drain out any water and stale gas from the bottom of the bowl. Later, I suspect, you may need to do a partial or complete carb rebuild, but let's not borrow trouble for now.
How long has the tractor sat before you started working on it?
When was it last running well?
What vintage is your tractor? (year).
Did it run on leaded gas originally?
Can you post pics of the tractor, carb shots, front to back, etc. to help figure out what may need to be done going forward?

Thanks,

CM
 
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   / Hesitation problem
  • Thread Starter
#5  
Coyote machine,

Yes I will post some pictures, also as you recommend I will make all the repairs to the point of the carb. should have it all done by tomorrow. Again, thanks
for taking the time to help.
 
   / Hesitation problem #6  
No problem.:thumbsup:
Age and hours on the tractor?
What gas did it use when it was new? Leaded or un-leaded?
 
   / Hesitation problem
  • Thread Starter
#7  
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   / Hesitation problem #8  
Coyote, the 1020 was built between 1965 and 1973. It definitely was designed to run on leaded gas.

duke, One thing I would like to add is the brand of spark plug. Right around the same time leaded gas disappeared, I stopped having any luck with Champion plugs in these JD utility tractors. I switched to Autolite and had much better success. Have you tried adjusting the carb at all? The needle valve screw near the top of carb adjusts idle mixture. SInce it is loading up at idle, I would try turning that screw in maybe 1/4 turn to see if it helps.
 
   / Hesitation problem #9  
OK! Now I have a better idea what you're dealing with:eek::confused2:
For the moment forget about adding a fuel filter in line to the carb. I'd break out a can or two of PB Blaster or whatever you use to loosen up stuck/rusted stuff and hit every bolt and clamp near the carb and especially where the carb attaches to the intake manifold. Then at the end of the intake tube feeding the carb go to the bottom of where it says inspect daily or once per century, and undo the clamp and carefully take the oil bath pan and dump its contents into your neighbor's stream, so it flows toward his house:shocked: Just kidding- dump it into a container of waste oil to get rid of later on.
Then see if in fact there is an element of some sort in the big canister above the label I spoke of earlier. I'd go to your favorite JD dealer's web site and with your model, serial number and such search for a kit to rebuild your carb. And get an intake manifold gasket too in case you need to replace the one you have already on there.
The rubber hose between the carb and air cleaner tube will also likely need replacing, but not necessarily. You want to find parts available BEFORE you take the carb apart to clean it. All the brown gunk on the outside of the carb is varnish from gas leaking, and dirt too.
I noticed a solenoid looking thingy stuck into the carb near the back, with a wire barely attached to it. You should be careful not to break the connection to that sensor. I'm not sure of it's function yet but I can say it is most likely crucial to the carb running properly.

I need to know what year this tractor was made, and whether it ran on leaded or un-leaded, how many hours on the clock, etc.
Gimme some history!:confused3: Please.:)
Do you have a service manual or anything like that?
Can you tell me where the wire on the sensor runs?
Good pics. Let's have some more of the wiring, fuse block?, anything that might proove useful.
What's the jumping deer insignia on the front grille for?:D
 
   / Hesitation problem #10  
Coyote, the 1020 was built between 1965 and 1973. It definitely was designed to run on leaded gas.

duke, One thing I would like to add is the brand of spark plug. Right around the same time leaded gas disappeared, I stopped having any luck with Champion plugs in these JD utility tractors. I switched to Autolite and had much better success. Have you tried adjusting the carb at all? The needle valve screw near the top of carb adjusts idle mixture. SInce it is loading up at idle, I would try turning that screw in maybe 1/4 turn to see if it helps.

Nice- you and I posted close together in time frame so I hadn't seen your answer to when it was made. The leaded fuel is a big clue and your spark plug preference is also very relevant.
What is the solenoid thing at the bottom of the carb, near the rear, supposed to do for you?
How often do you find you need to adjust the timing/dwell, and valve train on these puppies?
Is there no fuel filter at all on these models? And what grade of gas do these tractors run well on?
Do the floats in the carb ever fill with gas and need replacement. I suspect they are metal right....
Average HP on these?
Anywhere you can point to for good parts source?

Thanks,

CM
 
 
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