JD350 diesel fuel troubleshooting?

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Bruce
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JD350 diesel fuel troubleshooting?

Post by Bruce » Mon Dec 11, 2017 7:14 pm

Hello and thank you for any replies with assistance. My 350 straight diesel started to run rough then rev up good and rough again. To the point where it had no power and just felt like it wasn’t getting fuel. I then changed the fuel filters and started it back up. Ran good for maybe a min. Then started to cough and get rough again to the point where it didn’t seem like it would even stay running. Every so often it would rev up again on it own and then run Rough again. I believe it is a fuel problem and this is my first Diesel engine I have had. Any suggestions on how to trouble shoot this issue.
Thanks

dtoots1
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Re: JD350 diesel fuel troubleshooting?

Post by dtoots1 » Mon Dec 11, 2017 7:23 pm

believe you have run into the problem known as mouse turds or droppings.....this is a type of plastic or fibre seal in the injector pump.(that deteriorates over the years)...please do a search (at the top of late model tech support forum) on this site naming these and you will find a lot of posts covering this

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Stan Disbrow
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Re: JD350 diesel fuel troubleshooting?

Post by Stan Disbrow » Mon Dec 11, 2017 8:26 pm

Hi,

An important point regarding a diesel fuel system is the excess fuel sent to the injector pump must be returned to the fuel tank. If it is not, then the engine will act as you describe. Plugging of the return is commonly caused by the little pieces of that ring as it disintegrates.

Stan
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jsal
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Re: JD350 diesel fuel troubleshooting?

Post by jsal » Tue Dec 12, 2017 3:58 am

Sounds like a pump over haul remove the small plate on the side of the pump you will most likely find a lot of crud inside had the same
trouble on my 450C



JIM

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amos
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Re: JD350 diesel fuel troubleshooting?

Post by amos » Tue Dec 12, 2017 4:33 am

Old mechanical diesel engines are simple:you need air,fuel,and compression to get them to run.Yours is "hunting" but will intermittently run normally. That would eliminate low compression.Next easy check is air. Higher rpm's draw more air so to troubleshoot remove both inner and outer air filters and test run in a clean environment. If it runs normally change both filters no matter how "clean" they look. Had a dozer bogging down under load and found inner filter had been oiled by previous owner and though it looked clean it wouldn't allow correct volume of air through it.
If this test doesn't correct issue next test is a little more involved. First is to check for trash in fuel tank:there is a drain at the bottom of the tank. Drain the fuel and look for debris while draining. When tank is empty get a good flashlight and look from fill to bottom of tank. You're looking for mud,sediment or anything else other than fuel. Had a tractor starving for fuel and found a red rag in the fuel tank.
Once you know tank is clean then with tank still empty go to front of engine and disconnect fuel return line on injector closest to the radiator and with compressed air back blow though the return line and check for air flow at bottom of fuel tank(2 person job). If that checks clear you're almost done.
Now go back to fuel supply to filters at bottom of the tank: check for kinks make sure valve is fully open,and hand over hand inspect the line going to the filters. If all is good then put 5 gallons or so of new diesel in tank,vent filters and test run.
If it still "hunts" you need to remove injection pump and either replace or rebuild it.
BEFORE you remove the injection pump review the correct procedure as timing of the pump is critical.
If you don't want to remove the injection pump(fairly skilled job) another "old school" trick to free up an injection pump that is mechanically sound but sluggish or sticking is to add a quart of automatic transmission fluid to 5 gallons of diesel in the tank and run engine.Diesel is more oil than volitols (why they are called oil burners by us old geezers) and the ATF will sometimes free up a sluggish injection pump and will not harm engine.Used this trick on a dump truck I have that came from USAF and they use JP8 jet fuel in diesel engines. JP8 degrades over time to a sticky,waxy substance and it caused injection pump to stick. The ATF trick fixed it easily(after cleaning entire fuel system).
Amos
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Re: JD350 diesel fuel troubleshooting?

Post by Bruce » Tue Dec 12, 2017 5:41 am

Thank you everyone!! I will start troubleshooting tonight and let everyone know what I find. This machine gets used mostly to gather fire wood for 2 wood boilers. It is time to start gathering for next season and with out it I will be in a bad situation.....

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Re: JD350 diesel fuel troubleshooting?

Post by amos » Tue Dec 12, 2017 6:42 am

Hi Bruce,
Forgot to mention that when tank is drained you should disconnect fuel supply line at filter inlet and back blow the line to tank:there should be minimal resistance.The line itself though small should be easy to clear. The cut-off valve under the seat and back toward the fuel tank is usually the most common trash trap. It really sounds like your problem is a trash issue between tank and filter inlet.I've yet to find a clean fuel tank on any used equipment I've purchased and one of the first things I do no matter how good it runs is at the least inspect the tank to see what crud is in there.
Also: there is an algae that will grow in diesel. looks like mucus and settles to bottom of tank. On one of my newer tractors had that problem and I would be mowing and tractor would starve for fuel and die. Disconnect line,back blow by mouth,and tractor would run fine for a few minutes or hours then starve and die. There is a fuel additive that you can buy at most any auto parts store the has a bio-cide agent that will kill the algae but after running a tank of fuel you need to change the fuel filters as the now dead algae will foul them.
I have a good comfortable chair where I do my tractor and equipment trouble shooting and repairs. Work a little,have a seat and sip some coffe:think a little then work some more. That few minutes of sitting and thinking a little has saved me hours of unnecessary work.
Best of luck and don't forget to let us know what you find.
Amos
Pushin hard or diggin deep life is good.
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Bruce
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Re: JD350 diesel fuel troubleshooting?

Post by Bruce » Tue Dec 19, 2017 6:37 pm

Thank you everyone! I have fixed my issue for now. After pulling the tank fuel line from the lift pump I noticed it was barely dripping. Assuming it should be flowing out from gravity I blew back to the tank and had a buddy watching the inlet tube inside the tank with a light. He said an oily looking fluid came out. I still don’t have a real flash flood of fuel but I do have a steady dribble. I connected it back up and the machine seems to rev up and run much better. I’m not sure how much or fast that fuel will run out of the end of the hose but I plan on getting back at it in a few. Looking in the tank with a good light it appears to be pretty dam clean... we will see
Thanks all!!

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Re: JD350 diesel fuel troubleshooting?

Post by B Town » Tue Dec 19, 2017 7:00 pm

My 450C has a sediment catch and a fuel drain on the bottom of the tank. Do the 350's have this? I could not believe all the debris in that sediment catch!! I think your fuel should flow free and easy. I know my operators manual talks about draining out a cup of fuel from the drain on a regular basis to avoid this sediment build up. I do this routinely now, I want my machine to be dependable. Good luck, Bruce

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amos
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Re: JD350 diesel fuel troubleshooting?

Post by amos » Tue Dec 19, 2017 7:25 pm

Hi Bruce,
If you have 1/4 tank of fuel or better the fuel flow when you disconnect the fuel line at the filters should be a steady run with no dripping. At some point you should maybe pull the line and it can be cleaned with aerosol brake cleaner(be sure to clear the line of the brake cleaner when done). Don't forget the fuel cut-off valve under the seat may need some attention as well.Glad to hear you're up and running again without rebuilding the injector pump!
Thank you for the update too.
Amos
Pushin hard or diggin deep life is good.
What's ahead is what matters. What's behind is already done.
A fool of a man is he who doesn't ask questions...
God gave us 2 ears and 1 mouth for a reason...

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Re: JD350 diesel fuel troubleshooting?

Post by mikehutchen » Fri Jan 17, 2020 12:42 pm

just to pass along a little trick that I just discovered,
I have a 350 that would run then shut off just like you said that your tractor did, my fix
the leak off system of fuel from the injector pump back to the tank is gravity(fuel that is not burned will bypass injectors and return to tank)
on the diesel injector pump on top is the fuel bypass connection and connected to pump is a fitting and connected to that fitting is a small check valve with a glass bead inside, remove and clean check valve but do not damage the bead inside the check, clean with wd40 or something like that and blow all debris from check valve.
that check valve protects the diesel pump pressure from blowing a pump seal. also one must clean the tank because that is where the small particles of debris are coming from. if the check valve is clogged, the tractor will quit running. good luck

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Re: JD350 diesel fuel troubleshooting?

Post by Jim B » Fri Jan 17, 2020 4:27 pm

If you are finding material in the check valve on the injection pump my thoughts are there is a possibility the pellethane ring in your pump is failing. The larger of those pieces are often described as mouse turds, many posts here about them over the years, search pellethane ring. Sometimes they can also be seen if you remove the timing cover on the side of the injection pump. If it is some other type of material; either other components are failing in your injection pump or your fuel filter(s) are bad. In my mind the fuel filter(s) should plug before debris gets from the tank into the injection pump. With clean fuel, good filters and the injection pump in good condition I don't see where there will be anything in the check valve. About the only exceptions to that would be a machine that set for years and the fuel degraded inside the pump, dirt got into the outlet side of the filter during a filter change, or someone had the fuel line between the filter(s) and injection pump apart and got dirt into the fittings and line. In those cases probability of pump failure is higher.

I would not call the excess fuel return system gravity, it has to have some pressure. At times the tank fuel level is above the check valve and on some machines the fuel returns to a tank which is completely located above the pump. It is carrying excess fuel, under some pressure, being bled off to aid in cooling and lubricating the injection pump and circulating/warming the fuel in the tank, among other things. Any air bubbles are also purged from the injection pump via the check valve and return line. The check valve is intended to keep the fuel flowing one way and prevent air from coming back into the pump if it dumps into a tank above the fuel level.

Not saying cleaning the check valve didn't solve your immediate problem, just saying I think you need to keep watch and see what happens, your pump may be starting to fail. JMHO and understanding of the system, others may vary. I hope I'm wrong, I don't wish breakdowns on anyone.

Best regards,

Jim

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