706 Stalling

Kuch1982

New User
706 diesel started and ran fine this morning pushing snow. Then died on me twice. After letting it sit for a few mins, it went up and running again for 10 mins or so. Now when I try to start it, It fires for 20 seconds or so then quits. I let it sit for 10 mins, fires for 20 seconds and quits again. No idea what's going on. Fresh fuel. But, I bleed the air from fuel filters and it hisses for a couple of seconds. Tank is near full
 
Chech the fitting the return line on the top of the pump. Some of them had a ball check. Govoner flex ring will detiorate and plug it.
 
Try LOOSENING the two screw timing cover on injection pump side, if engine runs OK WITH the fuel leaking out, but dies with the cover tight, it's confirmed, injection pump needs removed for repair. The retainer ring fails inside over time and plugs the return line check valve fitting which is NOT on the injection pump on the 706 but at the BOTTOM of the fuel tank. Pump probably needs repair, and the tank drained to remove and clean the check valve elbow fitting of the broken coffee ground like bits that come from inside the pump. I have a JD 3020 pump apart now that came in for the same trouble.
 
Chech the fitting the return line on the top of the pump. Some of them had a ball check. Govoner flex ring will detiorate and plug it.
Ok, so I don't hear fuel running back to the tank like usual, so after some reading, I'm going to start looking at a plugged return line. Being new to diesels, what should my process be? Remove line off pump and blow air towards the tank to see if it's plugged? Or?
 
Am I understanding correctly that you are repeatedly getting air out of the fuel filters? It's never gonna run right until you figure out where that air is coming from.

Does a 706 have a water trap like a 460? If so, you could be pulling air in between the jar and the warped jar-head under a high vacuum situation caused by a restriction at the fuel tank outlet. The water trap on the 460 is a very thin casting and a soft jar gasket and will warp from the pull of the bail over time.

This could also occur with any rotten fuel lines that may be present.
 
Ok, so I don't hear fuel running back to the tank like usual, so after some reading, I'm going to start looking at a plugged return line. Being new to diesels, what should my process be? Remove line off pump and blow air towards the tank to see if it's plugged? Or?
You probably don't hear fuel coming back BECAUSE the return check valve fitting is PLUGGED from the failing retainer ring inside the pump. If engine will run WITH THE TIMING COVER LOOSE, PUMP needs repaired and the return valve removed and cleaned.
 
No water trap to speak of. Assuming the return line is plugged, would that cause some ba k pressure?
YESSS!!!!! DO NOT just clean the return valve and keep running tractor either thinking all is well, after awhile you WILL SHEAR off the retainer pins, SIEZE the hydraulic head, and BREAK the drive shaft!! I've seen that happen too many times in my forty plus years of injection pump repair..
 
You probably don't hear fuel coming back BECAUSE the return check valve fitting is PLUGGED from the failing retainer ring inside the pump. If engine will run WITH THE TIMING COVER LOOSE, PUMP needs repaired and the return valve removed and cleaned.

Try LOOSENING the two screw timing cover on injection pump side, if engine runs OK WITH the fuel leaking out, but dies with the cover tight, it's confirmed, injection pump needs removed for repair. The retainer ring fails inside over time and plugs the return line check valve fitting which is NOT on the injection pump on the 706 but at the BOTTOM of the fuel tank. Pump probably needs repair, and the tank drained to remove and clean the check valve elbow fitting of the broken coffee ground like bits that come from inside the pump. I have a JD 3020 pump apart now that came in for the same trouble.
Ill attach a pic...what bolts do I loosen? Sorry....New to diesels.
 

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The two screw TIMING cover plate on the injection pump side, if engine runs OK WITH the cover loose so fuel can leak out, that proves the pump needs repair and return line/elbow cleaned..
Thank you. But just a question. If I just try to clean the return and have it run just to get it close to the shop to play with the pump, can I just remove the return line at the pump and blow air into it? No bleeding lines necessary? Just need to get it moved from field to shop for now until I have a better place to remove pump
 
Thank you. But just a question. If I just try to clean the return and have it run just to get it close to the shop to play with the pump, can I just remove the return line at the pump and blow air into it? No bleeding lines necessary? Just need to get it moved from field to shop for now until I have a better place to remove pump
I've loaded otherwise dead tractors on trailers by letting fuel out of the pump side cover while driving and loading on the trailer, but a bucket under the frame rail and drive to where you want it to work on. MAKE SURE pump timing marks are aligned before removing the pump too, DON'T just yank it off or you will make more work for yourself later getting it back on.
 
I agree with Dieseltech . He rebuilds pumps and knows what he is talking about. He's a good guy to send your pump to for the repair work too. Not trying to pitch for him just that he knows what he's doing and you sound pretty new to working around diesel engines. And those don't have a water trap like your 460 does. They have the same filter system as my 806 does unless it has been modified in the last 50-60 year.
 
I've loaded otherwise dead tractors on trailers by letting fuel out of the pump side cover while driving and loading on the trailer, but a bucket under the frame rail and drive to where you want it to work on. MAKE SURE pump timing marks are aligned before removing the pump too, DON'T just yank it off or you will make more work for yourself later getting it back on.
Ok, so I took the return off just for shits and giggles to blow some air through the tank, I can definitely hear the air getting to the tank, but once hooked up, she dies again. Loosened cover like you said, and runs better, but still wants to stall out. I guess I'll remove the injector pump and have it rebuilt. Again, I am totally new to diesels, so can you give me a breakdown on removal process?
 
Ok, so I took the return off just for shits and giggles to blow some air through the tank, I can definitely hear the air getting to the tank, but once hooked up, she dies again. Loosened cover like you said, and runs better, but still wants to stall out. I guess I'll remove the injector pump and have it rebuilt. Again, I am totally new to diesels, so can you give me a breakdown on removal process?
Best to get a service manual, but the pump to engine timing should be set first BEFORE removing the pump to make going back on easier in the future. Remove the two screw timing cover on the pump side, then turn engine by hand until the two marks inside are aligned. If I recall when they align the Flywheel mark should be at the TDC mark. Turn off the fuel under the tank, remove lines and linkage as needed and remove the pump assembly. While pump is off I like to DRAIN the fuel tank to remove and clean the pump top return line check valve elbow under the tank, There WILL be coffee ground like bits that usually plug that fitting and cause the repaired pump to shut down too. I have a JD 4520 pump apart in the cleaner now that came in for the same trouble.
 

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