JD-850 FUEL Return

[DogDiesel]

85 JD-850 4x4. Yanmar 3T80J engine. Previous owner say he had the injector pump rebuilt and geadgasket replaced.
Background. Tractor would not run when I got it, PO thought it was a compression issue. Cranked but would not start. After I replaced every rubber fuel line, and bled the system, it bleeds off and runs. Some of the rubber had green paint on it, and the PO owned it for 23 years. The rubber fuel lines were leaking and not sealing correctly.

Today's problem: Absolutely NO FUEL ever runs out of the return line to the fuel tank. I get fuel if I bleed the injectors, not a gush, but it bleeds and starts. I pulled the return line from the tank, filled the line with diesel, filling the thermostart reservoir. Presurized the system. Previously, it would run, but never fill the reservoir. Starts every time, after sitting. It is bled. I presurized the tank at the return line, and no weaps or leaks. Tractor runs smooth and fairly strong. I rototilled my garden as a test with a 72" Kingcutter rotortiller, and it would get down 8 inches, but I was working it. Tends to droop in teen RPMs under moderate load, works strong near full throttle.

Question: I should get fuel return back to the tank, right?

Wayne

 

[BATTY54]

On my 850 it only has return fuel to the reservoir when you use the foot throttle, rev it up and back off, you will get a small amount of fuel to the reservoir not steady.

 

[chriswheeler]

Rebuilt my 950, almost the same tractor. The fuel return gets very little flow on these, even with a new fuel pump. If you have all the air out of the system and no air leaks in the fuel supply lines or filter, it should run fine. Make sure the fuel filter is clean or just change out for a new filter. When rebuilding my 950 I noticed that the fuel delivery to the injectors was weak when bleeding air from the lines at the injectors connecting lines top of the motor. Ended up getting a new pump from Hoye Tractor and that more than doubled the fuel delivered. You could have a tired pump. Hoye sold a aftermarket pump quite reasonably ($500 or so ) when John Deere wanted almost twice that. Diamond Diesel, who rebuilds diesel fuel pumps, said that it would cost more to rebuild my pump than buy a new one for a pump that small. Even with a new pump, flow coming from the return was very little, old pump was none at all. You could end up needing a new pump, if so, I'd give Hoye a call.
Chris

 

[DogDiesel]

My tractor is fixed. Runs strong. StartStart EZ. Just seemed like too little return fuel.
Wayne

Rebuilt my 950, almost the same tractor. The fuel return gets very little flow on these, even with a new fuel pump. If you have all the air out of the system and no air leaks in the fuel supply lines or filter, it should run fine. Make sure the fuel filter is clean or just change out for a new filter. When rebuilding my 950 I noticed that the fuel delivery to the injectors was weak when bleeding air from the lines at the injectors connecting lines top of the motor. Ended up getting a new pump from Hoye Tractor and that more than doubled the fuel delivered. You could have a tired pump. Hoye sold a aftermarket pump quite reasonably ($500 or so ) when John Deere wanted almost twice that. Diamond Diesel, who rebuilds diesel fuel pumps, said that it would cost more to rebuild my pump than buy a new one for a pump that small. Even with a new pump, flow coming from the return was very little, old pump was none at all. You could end up needing a new pump, if so, I'd give Hoye a call.
Chris

 

[greenj1959]

My tractor is fixed. Runs strong. StartStart EZ. Just seemed like too little return fuel.
Wayne

hello I just signed to this site I have an older 850 I'm glad to know they dont have a lot of return because I thought I had a problem. the problem I do have is that there is fuel leaking from the intake where it bolts to the head. when I crack the lines to a the inj there is noticeable rpm lose which is good, any thoughts before I start to take it apart/

thanks jim

 

[Barry 1]

hello I just signed to this site I have an older 850 I'm glad to know they dont have a lot of return because I thought I had a problem. the problem I do have is that there is fuel leaking from the intake where it bolts to the head. when I crack the lines to a the inj there is noticeable rpm lose which is good, any thoughts before I start to take it apart/

thanks jim

Did you try to tighten the bolts? If fuel is leaking out,then dirt can get sucked in.The thermo-start is probably leaking fuel into the manifold,and will probably need to be replaced.

 

[greenj1959]

I didn't tighten anything yet .There shouldn't be any fuel in the intake unless you us the cold start right? I also have a new gasket on order and I will also get the cold start coil. thanks for the reply I need to get more wood out yet.

 

[Barry 1]

Right.John Deere wants $141.08 for the thermo-start(CH14079) ,but you can get it from HoyeTractor.com for $44.95(TS-1)

 

[DogDiesel]

John Deere has priced themselves out of my business, and based on your quotes yours also.
When I get this JD-850 painted and near 100%, it is gone, cause "Green" is too expensive to operate on my farm.

The only "Green" I will keep on my farm is a Gator 6x4.

Right.John Deere wants $141.08 for the thermo-start(CH14079) ,but you can get it from HoyeTractor.com for $44.95(TS-1)

 

[chriswheeler]

I guess the high priced Deere parts thing cuts both ways. I have lots of neighbors with tractors and it seams some price their parts much cheaper, but in the end they always seam to end up with more problems needing more replacement parts. Had a Yanmar, it was a very reliable tractor, and when it did need parts, they were much cheaper than Deere parts. Trouble was, even Hoye tractor, the parts supplier couldn't get every part, some things just weren't available for any price. Deere, even though expensive, has never failed to have something I need be available. What I'm talking about here is product support, some just don't have it, some do. I'm sure the price for maintaining that availability is passed on to the customers in the price of the parts as well as some price gouging. That 850 was a very reliable tractor in it's time, and still should be in good condition. but only you know what it's been through in it's service life. Might want to give a good look at what the replacement will cost before making that decision.
Chris

 

[DogDiesel]

Chris,
When I spoke I was the adult in the room. I am a diesel mechanic, own a farm, so certainly not a greenhorn from suburbia. Great little tractor other than its color. I made no mistake in my posting. While this thing is cute and works good, it has no position on a real farm. Its 10 or more HP for its size short in PTO area, a tad light, too. Really needs the tires weighted. I have a set of rear weights that will go with it.
I bought this tractor and had it running within an hour. My post was about fuel return flow or seemingly a lack of it. Its not a keeper, never was.
It would already be gone, for a good price and with a happy buyer, except I have recently been grounded by the VA Doc for a pulmonary condition. When I get the green light from Doc, the 850 will get shiny green paint, and a new owner.

I guess the high priced Deere parts thing cuts both ways. I have lots of neighbors with tractors and it seams some price their parts much cheaper, but in the end they always seam to end up with more problems needing more replacement parts. Had a Yanmar, it was a very reliable tractor, and when it did need parts, they were much cheaper than Deere parts. Trouble was, even Hoye tractor, the parts supplier couldn't get every part, some things just weren't available for any price. Deere, even though expensive, has never failed to have something I need be available. What I'm talking about here is product support, some just don't have it, some do. I'm sure the price for maintaining that availability is passed on to the customers in the price of the parts as well as some price gouging. That 850 was a very reliable tractor in it's time, and still should be in good condition. but only you know what it's been through in it's service life. Might want to give a good look at what the replacement will cost before making that decision.
Chris

 

[chriswheeler]

Post was not intended to be some sort of personal attack or even personal critique, just a statement of what I've seen as well. Hope no offense was taken. Your application only you will know and be able to judge. My experience with diesel engines is limited to large stationary stuff, little with stuff that can move. If you need to pull a 12' disc, it's sure not the right machine around your parts. Good luck with the VA, I'm lucky enough to have not needed to go down that road yet, but I could surely meet you in line there some time for the same reason. Again, hope no offense was taken, mine was a comment on quality, not suitability to your application or situation.
Chris

 

[brooke1b]

Help I have the same issue, does the fuel reservoir and lines that return to the tank need to be full. Mine are not sand it won't run. I also see bubbles coming out around an injector. I am assuming that is sucking air.

 

[DLTTrekkers]

Pushing air out. Did you replace the internal washers ?

 

[brooke1b]

If you were talking about the ones around the injectors I have not. I have not been able to get the injectors out and I'm not sure if they unscrew or pull out. They are very tight in there.

I will tell you how it started and what I have done.

The tractor head white smoke coming out of the bypass tube so I thought I would clean out some of the lines and the fuel filter to see if that helped it did not. Then took off the lines to the injector pump which is gravity fed and bleed the lines. That didn't help. i then tried to take out the middle of three injectors but it wouldn't come out and so I put the screws back on it and screwed it in but may have over tightened it and shoved it into the hole about a centimeter further than it probably should. then the tractor started smoking black smoke out the stack. Drove it around the lawn and it's still smoked black. Then unfortunately I decided to take the fuel pump out and disconnect the governor and cleaned it and put it back in and ever since then I haven't been able to get the tractor started. But it may be because I have air in the lines going to the reservoir tank that feeds the glow plug. I have disconnected the fuel lines at the injectors multiple times and I get some fuel spitting out of each one but not enough to fill up the reservoir lines.

 

[jd110]

The reservoir for the glow plug does not need fuel in it to run. It will fill on its own after it runs for a while. There is a very small amount of return fuel from injectors. If you need fuel for the glow plug before it is full, you could fill it manually. Is the fuel rack on the pump moving when you move the throttle? If the linkage got bent when you removed the pump, it could bind and not allow it to move to the run position. Also, did you disassemble the pump when it was out? The copper washers that seal the delivery valve holders should be replaced. If the copper washers leak, it won't allow pump to build pressure and tractor will not run. The leak will not leak to the outside where you can see it. It leaks internally.