What's wrong with my tractor? Engine? Injector Pump?

[tomd999]

Hiya,

Have you checked?

1) Thermostat opens at the right temp?
2) Belt is tight enough. not glazed and is actually turning the water pump?
3) Water pump is actually pumping water? (I have seen impellers fall off)
4) The coolant for combustion gases? (test kits from an autoparts store)
5) If it's turbocharged, is it working? ( a stuck turbo is a huge restriction)
6) Spark arrester screen for clogging?

(5 and 6 are long shots, you would notice these right away most likely)


Most of the time when you have a fuel restriction you will get a whiteish grey smoke and declining power as you put more throttle in. They will idle great and just die under load. The other side of a plugged fuel supply is it will run cooler as there is less fuel burning to heat it up. If you have a turbo, the pump may have a compensating valve that applies additional fuel as boost rises, that can go bad too and kill power but they fail to less fuel and less fuel is less heat so I wouldn't look to a underfueled issue. An overfueled condition would result in heavy black smoke like you see on the modified tractors at the sled pulls. A 4yo can spot an overfueled Diesel, "Wow daddy, look at all that black smoke", they are unmistakable. Overfueled Diesels run hot but they run hard and make tons of power, not your troubles. I wouldn't look at the fuel system as a primary cause here.

I would look to the cooling system. A blown head gasket can let combustion gasses into the cooling system and force coolant out of the head area, that additional gas would heat the head area very quickly and would be vented by the radiator cap. You may have a crack in a casting that opens as the engine heats and releases gasses into the coolant, same result however with either of these I would expect it to develop a miss which yours doesn't have, so these are less likely.

I would look to coolant circulation. Plugged core, plugged or non working thermostat, plugged coolant passages in block/head, sediment in coolant passages, water pump impeller/broken shaft, belt, fan clutch, pulleys.

Afterthoughts: 12 yo gear tractor, hows your clutch? Dragging brakes? You didn't replace the lower radiator hose recently and leave out the spring did you? Your using 50-50 coolant mix not straight well water are you?

As always, 2 cents worth,

Tom

 

[dqdave1]

You messed with the fuel lines and it ran ok for a little longer than before. Might be on to something here. A rubber fuel line may be collapsing and restricting fuel flow. Fuel tank has garbage in it and is clogging flow ( you messed with it and it unclogged for a while. Blow back through fuel line to tank. You nay be sucking air on fuel line somewhwere. Faulty injector?\ Next time it boggs down; open fuel cap and see if it perks back up.

 

[jake98]

My JD is old and it used to get crap cloging in the tank. I'd hook an air hose to the tank line and you could hear it blow it out back into the tank, after the clog was gone it was just bubbling. Happened all the time untill I finally got the tank clean.

 

[Gary Fowler]

I think I would replace all the old hoses that you indicated were cracked. Sometimes fuel hoses which are minimum 2 plys will collapse internally with no evidence externally. Also I would remove all the fuel from the tank. Remove any internal screen and fitting from the tank outlet and drain all the fuel into a container so you can see if it has any fouling material. There could be some algae present that was in your last fuel supply that is fouling the intake to the injector pump. Completely drain, rinse with some fresh diesel and then reinstall everything piece by piece and do a good visual check and pressure test for restrictions. Also check that your fuel cap is breathing. I think that was mentioned previously, a stopped up fuel vent will not allow the proper fuel flow. I dont think the slightly elevated operating temperature is connected to your power decrease but is a seperate problem unrelated to the fuel. Recheck your fuel filters also after cleaning the system to assure no contaminants are present.

 

[Saxman]

Let me throw something out to discuss, has anyone had trouble with algae in their fuel. We have this problem from time to time at work, it is worse with the new ULSD fuel. These organisms live in any moisture in the fuel and live off the fuel they leave deposits which can foul the fuel lines, filters and pump. Truck stops and truck dealers carry algaesides to deal with it, power service, howes and other addititives will not do the trick for this. Anyone else experience this?

 

[dmccarty]

I'm also wondering about water in the fuel. Got water in my fuel tank once and it was not fun. Might want to drain the tank and put in fresh fuel. Won't cost anything to try.

Does the tractor have a fuel filter bowl with a ring that floats to indicates water?

You could also take an oil sample and have it tested. They might be able to see something in the sample regarding the engine.

I was wondering about the thermastat but the overheating seems to have gone away.

Later,
Dan

 

[npaden]

Okay, I talked with my friend who is a mechanic and I told him something that he thought was a big deal. Remember earlier when I mentioned that it wouldn't turn off with the key and I thought it was the fuse? Well at one point in there when I was messing with it, (I ended up replacing all the fuel lines, it cost less than $10 to replace them all) it started to turn off with the key again and I didn't replace the fuse. It just started working again. Based on that he now suspects that it is the injector pump.

I checked the price online and it is $877.70. He's going to be in town sometime within the next couple weeks so I might just have to wait until he gets here to look it over and see what he thinks. He works on John Deere Construction equipment for a living and actually seems like he knows what he is talking about!

 

[WTA]

I just started reading this thread and wish I had seen it earlier. I hope you haven't bought a pump for it yet. In the 5 years I worked as a Kubota mechanic I think I only had to rebuild about 3 or 4 of them. My dealer sold case and Massey too and I was doing one or two of those a week. Kubotas just don't go bad that often. Not on ones as old as yours yet anyway.

We are on the East side of Lubbock near Idalou if you want me to look at it. I'd almost be willing to bet it's junk in the lines. Also you may have created a problem by replacing the ones you did. It has metric sized lines on it and if you got generic fuel line from the parts store in standard size then it's probably smaller now.
I'd first blow back the fuel line from your first filter to the tank, If that doesn't work then dump the fuel and refill it completely. If it works good after that then you can still reuse the fuel you take out.

Probably the most common thing I have had to fix for this problem, but it doesn't explain your failure to shut off problem, is bad main bearings. This is one of the models I remember as being particularly weird about it when your ground strap goes bad near the starter. The current goes through the crank and bearings instead and burns them together with the arcing. I know that is a stretch for a lot of you to believe but I've seen it quite a few times. The symptoms are identical.

The failure to shutoff problem was probably junk in the fuel shutoff solenoid jamming it. You need to use a volt meter or test light on those to see if the switch is actually killingpower. If it does but it stays running then the solenoid is bad. If I remember right there is a inlet screen on the injector pump that could be clogged too. If it is a model with a mechanical fuel pump then that screen could be clogged as well. I haven't worked on these things for a living since 01 so I'm a little out of date.
If you need some help figuring it out then just let me know ok. I'd go dump and refill that fuel first myself. Twice now in Lubbock I have gotten gasoline out of a diesel pump so it does happen. The first time was out of a private tank on someones farm and it blew up a 671 detroit that I was driving. Those old two strokes really don't like gas going through them at WOT. The second one was from a gas station and it went in my power stroke. They admitted filling the wrong tanks there and paid for it.

By looking at your website, we have a lot in common and should get together sometime anyway. I'm retired Navy and we are planning a round the Western Pacific cruise sometime in the near future. As soon as I find a sail boat that can do it. And a place to park it when we are back here at home. I really miss the ocean.

 

[tomd999]

Hiya,

The electrical fuel shutoff valves I have seen were of the type that shut the fuel flow off by a spring if the current was switched off. Since yours dosen't shut off the fuel when you turned the key off, I wonder if there could be something stuck in it stopping it from working correctly. If there is, that could also be a restriction that hinders fuel flow when in opperation causing loss of power.

Tom

 

[RobJ]

Probably the most common thing I have had to fix for this problem, but it doesn't explain your failure to shut off problem, is bad main bearings. This is one of the models I remember as being particularly weird about it when your ground strap goes bad near the starter. The current goes through the crank and bearings instead and burns them together with the arcing. I know that is a stretch for a lot of you to believe but I've seen it quite a few times. The symptoms are identical.

Man this is really outside the box. The ground strap is bolted to the block or frame, the starter is on the frame. The bearings are not in the shortest loop. I really don't see any way the mains could arc. if so this would happen all engines. Plus it could ground through the pistons, rings.

On the metric lines vs sae lines, these tractors don't use that much fuel, going from 3/8 to 5/16 to even 1/4 inch would cause fuel starvation.

I do agree that pumps don't go bad as much as people think they do.

good luck,
Rob