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Good afternoon everyone!

I have a 1993 JD 425, 1320 hours, very clean, and well maintained machine. I have had a few issues with the machine that I have been able to resolve thanks to the help of everyone on this board, however I am having a peculiar issue with the tractor that I am looking for some help on.

Yesterday I was riding around the yard doing some spring cleanup when out of the blue the tractor just stopped running. I needed to choke the machine to get it running again, and had to adjust the choke up and down just to keep it running. it seemed to calm down so I continued riding around. about 10 minutes later it did the same thing, however this time it took about 5-6 times at turning the machine over in order to keep it running ( again with the choke on) until it calmed down.

Here are some stats-

-tractor fires each time it is turned over, just wont stay running
-have to have the choke on even if its warm until it calms down

things I have replaced so far

TDM
Igniter
plugs
battery
starter/ relay ( another issue)
seat switch

I am beginning to think that this is fuel related but before I remove the rear fender and get into the gas tank I wanted to throw this out here to anyone that might have another idea


thanks in advance for any help you can give!!

Don
 

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Good afternoon everyone!

I have a 1993 JD 425, 1320 hours, very clean, and well maintained machine. I have had a few issues with the machine that I have been able to resolve thanks to the help of everyone on this board, however I am having a peculiar issue with the tractor that I am looking for some help on.

Yesterday I was riding around the yard doing some spring cleanup when out of the blue the tractor just stopped running. I needed to choke the machine to get it running again, and had to adjust the choke up and down just to keep it running. it seemed to calm down so I continued riding around. about 10 minutes later it did the same thing, however this time it took about 5-6 times at turning the machine over in order to keep it running ( again with the choke on) until it calmed down.

Here are some stats-

-tractor fires each time it is turned over, just wont stay running
-have to have the choke on even if its warm until it calms down

things I have replaced so far

TDM
Igniter
plugs
battery
starter/ relay ( another issue)
seat switch

I am beginning to think that this is fuel related but before I remove the rear fender and get into the gas tank I wanted to throw this out here to anyone that might have another idea


thanks in advance for any help you can give!!

Don
Don, I have a 455 so I am very familiar with the chassis and the other operational issues other than mine is the diesel. I would bet money your problem is caused by the fuel system and I would start with the carburetor. If I recall, the 425 has a carb where the 445 is fuel injected.

If your tractor is requiring the choke to start and run, it is definitely fuel system related. The carb likely needs a rebuild and it isn't that difficult. I would order a new needle and seat and a carb gasket kit. Also replace the fuel filter which is in the inline fuel supply line from the tank. The float needs to be carefully checked to make sure it doesn't have a hole in it. Simply floating it in a glass of water will demonstrate if it has a leak plus when you remove it, it should NOT have any fuel in it or rattle like it has anything inside it.

I don't see any need to get involved in taking off the rear tub or fender assembly at this point. The fuel pump, when not functioning will generally either work or it won't. If you notice that the tractor bogs while on an uphill incline while running strong on a downhill decline, then I would say there is a possibility of a fuel pump issue but generally, when a pump goes, it goes and doesn't pump at all.

This isn't as imposing as it may sound, even if you have to pull the rear body tub assembly. After all, once you unbolt the seat assembly and unplug the tail lights, there are two bolts under the seat which secure the upper deck and then there are a total of 4 bolts between the two foot rest panels and the tub lifts right off. I have had mine off so many times I can do it in about 10 minutes tops. I would suggest that if the bolts in the footrest are at all rusty, which happens if you use your tractor in the winter for snow, then replace that hardware with stainless bolts and nuts from your local hardware for about $2.00 as it makes future tub removals so much easier.

If you have to use the choke for it to run, it is definitely a carb issue. Let me know if I can help. I may have the service manual for your tractor from which I can get information you may need. Feel free to send me a private message if I can help.
 

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Don, this is a blowup image on the carb on a 425

 

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Don,
You will need the engine number off of the tractor motor to obtain the correct carb parts. The engine number is either a FD620D-ASo2 or BS02, or CS02, Ds02, ES02, GS02.

You will need to know exactly which engine number you have to get the right parts. Also I would suggest taking your tractor's serial number off of the frame tag on the right side of the frame, just ahead of your right foot rest.

Hope this helps. Here is the link to the specific page in the John Deere parts catalog.


John Deere - Parts Catalog
 

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Don
I had the same issues with my 425 a couple years ago, basically did the same things you have tried, I ended up taking it to the JD dealer, they had it for a week and could not find anything wrong, I got it back and it did the same thing again. I took it back and they finally found what they claimed was a bad electrical connection on the left side of the engine. There is a electrical connection plug near the frame that they said they disconnected it and plugged it back together several times. So far I have not had an issue since.
 

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I would check the fuel pump itself. If the pump is similar to the 445 pump, they have a small piece of fuel line as part of the pump. If that piece of fuel line splits, which they are known to do, your fuel pressure to the carb will be all wacky. The tech manual give possible faulty fuel pump symptoms as engine cranks but does not start, erratic running, poor high speed operation. etc. This is a known issue with the 445. Don't know about the 425.
 

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Don
I had the same issues with my 425 a couple years ago, basically did the same things you have tried, I ended up taking it to the JD dealer, they had it for a week and could not find anything wrong, I got it back and it did the same thing again. I took it back and they finally found what they claimed was a bad electrical connection on the left side of the engine. There is a electrical connection plug near the frame that they said they disconnected it and plugged it back together several times. So far I have not had an issue since.
Techie1961 wrote a thread awhile ago about this electrical issue which Red Badger is describing. There was a connection within his actual plug where one of the spades had actually either broken off or simply pulled back out of the plug, causing all sorts of unpredictable weirdness. But the fact that it takes the choke to get it running again means it is likely leaning out, requiring less air and more fuel, which is why the choke is effective in getting it running.

It would be advisable to take the electrical plugs on each side of the radiator and carefully disconnect them, VERY CAREFULLY EXAMINE the internal components of the actual plug itself and make sure that somehow one of the connections isn't compromised. Inspect each plug with a light and then make sure to clean them and spray them with a electrical connector protection to prevent any corrosion and clean them up which may just solve your issue.

Techie1961 has a stable of 445 and 455 but I am not sure if he has any 425's but I would encourage you to search his postings in the Lawn and Garden tractor search tool.

Techie1961 has built himself a tremendous shop and he has lot's of pictures and even a couple of threads on the subject. So when you search his postings, make sure to stay in the Lawn and Garden tractor subsection or you will have much more stuff to search through. I encourage you to check out his historic barn to shop transformation when you have time. It is impressive.
 

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Discussion Starter #9
All-

thank you for the advice. I will be checking out the electrical connections, fuel pump and system as well as giving the carb a good rebuild. I will post once all is completed

have a great day!
 

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I would start with the simple things first, like the fuel lines. My 425 had a crack in the fuel line near the carb. It behaved as you described. I assume the cam has been replaced and they also replaced the governor gear? Wouldn't hurt to inspect all connectors and fill with dielectric grease. Though, I doubt your problem is electrical.
 

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Discussion Starter #11
So... I am in the process of removing the carb and I noticed that it looks like there is a vacuum fuel pump that someone has added to the machine and is located right next to the carb.

it has three ports on it.

one for fuel to come in, once that goes to the carb and a 3rd that goes to the right side valve cover... probably for vacuum? anyone seen anything like this? my guess after seeing the diagram above and what I have, is that the original carb has been replaced and for some reason they used a vacuum pump. after noticing this, I turned key on and listened for the pump in the tank and I am hearing nothing. is it possible that someone bypassed the tank pump for this pump?

ill send some pics tonight when I get home from work as now my mind is not going to let me sleep....

thanks again everyone!

Don
 

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All-

wanted to give you a follow up as I found some interesting surprises once I started digging into the fuel system.

1. fuel pump was not operating
2. previous owner did not replace the pump, however decided to bypass it and install a vacuum pump near the right side of the carb
3. vacuum line was installed into the valve cover using something similar to JB weld....
4. fuel pump was getting power but was rusted out, and there was a ton of debris in the tank


I am replacing the entire fuel delivery system and have cleaned the tank. new valve cover without vacuum line has been installed. I should have it back together this weekend if the pump gets here by then

there are some pictures below. this type of cob job makes me sick.
 

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Sorry to hear you got stuck with that mess.That was a skinny doogen job that could've resulted in a fire.
 

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Update on 425

All-

to anyone following this thread, I wanted to give an update. Fuel system has been completely replaced and tractor seems to be running better than it ever has for me. In addition to the problems that I described above, the tractor also smoked a bit upon cold startup. now that there is no vacuum coming from the valve cover that issue has subsided aswell. Thanks again to everyone who had advice on what to look for. I really appreciate everyone's insight and expertise!
 
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