International 986 Sputtering and Dying

[justin2988]

I inherited my grandfather's 1981 International 986 and it has been a great tractor, but last Fall I was pulling a plow behind it getting ready to plant some ryegrass and the tractor started sputtering with RPMs going up and down for about 20 seconds and then it died. I was able to crank it back up with ether, but the RPMs were going up and down, and after about 20 seconds it quit again. Again, cranked with ether, tractor ran rough, was able to give it a touch of ether to keep it running, limped it out of the middle of the field and parked it under a tree and left it there until this afternoon. Today the tractor was sluggish to start but once it fired I was able to drive it around smoothly for about 1,000 feet but then I could hear it start to sputter and slowly it died again, same behavior as before. Pretty sure it's a fuel issue but it's got fresh fuel in the tank and two fresh fuel filters. I cracked the rubber fuel hose between the filters and the pump and pushed the primer in and out and fuel was flowing out good of the hose and the primer had good pressure. Was wondering if anyone had any ideas on what is causing this issue? See photos for my fuel pump, filter, and lines setup.

 

[K5lwq]

When you say it has fresh filters is it different ones than what is pictured?

 

[justin2988]

When you say it has fresh filters is it different ones than what is pictured?

I installed those on May 9, 2020 and only put 8 hours on the tractor since then. Same filters are still on the tractor.

 

[K5lwq]

That what I was thinking might be the case. The filters were on the tractor when you first had issues. It could be possible that you got some bad fuel that has stopped up the filters again.

It may be worth replacing them again. If it does not correct the issue you will have a back up set for the future.

 

[Roadworthy]

Pull the fuel line at the first junction after the tank. Get a jar or a bucket and observe gravity flow directly from the tank to ensure you have a good, unobstructed flow. You could have crud in the tank. Of course after this exercise you will need to bleed the air from your system.

 

[justin2988]

Replaced both fuel filters but the issue persisted. Tractor would run for a minute or two then starve for fuel and die. Did as Roadworthy suggested and disconnected the fuel line going into the primary filter housing and fuel was barley dripping out. Put my air hose on it, removed the fuel tank lid, and blew air up the line and first some milky sludge and then fuel came gushing out. Reconnected the line, purged the air, and the tractor ran perfect afterwards. I'll probably have to battle this again now that I know there's some gunk in the tank/line, maybe even drain and clean the tank, but now I know what to look for.

Are there any recommended diesel additives to put in the tank to help prevent this from happening?

 

[Richard]

I once cleaned out my fuel tank on my JCB backhoe/loader. Took the bottom plug off, got the pressure washer out and simply had at it. Let the pressure and water scrub the tank. When I was done, I took a garden-sprayer (pressure sprayer) and put a gallon of diesel in it. pumped it up and sprayed the entire inside of the tank with diesel....to ostensibly get rid of the water.

Put plug back on, filled it up and was done. Worked like a charm for me.

 

[CADplans]

"Fresh" fuel filters on a diesel has almost nothing to do with "hours",,
fresh fuel filters has more to do with "months"
depending on your fuel source,, fresh filters may be old at 6 months,,

Don't be surprised if the problem is the filters,,,

 

[scooterj1234]

I had a 966 had same issue. Took fuel cap off, lowered a stick until felt resistance, then pushed almost 2 more inches thru the mud...when the mud settled out it would run ok, but bounce it around for awhile and the problems would arise. Sold tractor without fixing it, told the new owner about it tho.

 

[pmsmechanic]

Two instances come to mind. On the first a Deutz tractor with the same issue. Turned out to be a leather glove in the fuel tank. It would settle over the fuel outlet and choke the flow of fuel off. No rhythm to when it would happen. Just all of a sudden the tractor wouldn't run.

Second was a Versatile swather where the owner had neglected to reinstall the fuel cap after filling. The gas tank was full of dead moths. You'd drive for a while and all of a sudden the engine would stop. Most times you could restart but not always. Once we drained all of the fuel and installed a rolled up piece of window screen into the fuel outlet the problem was solved.

Good luck