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

[KennK]

Unfortunately I speak from experience here ...

Make sure you didn't somehow use gasoline instead of diesel fuel. Open up the fuel cap and take a good whif. You should be able to smell the difference.

Boneheaded me did that with my tractor. It started smoking, loosing power, and then eventually wouldn't start. The dealer just drained out all the gasoline, replaced the fuel filter, and things seem OK now ... I hope.

Long story on how it happened related to an oddly marked pump.

 

[crashz]

The blead screw on the pump should pee fuel when removed and the tank feed is on. It most likely has nothing to do with the pump itself, but fuel delivery to the pump. On my tractor, the fuel feed to the pump is gravity, and the slightest amount of sediment can clog it enough to starve the machine. I've never closely looked at the Kubotas, but I imagine the are the same.

So you know that you are getting restricted flow to the injection pump, try disconnection the line and seeing if you get good flow right after the fuel filter. Keep working your way back to the tank if you don't see any improvement is flow. Under gravity flow with a 1/3 of a tank of fuel, the flow from my JD is a constant stream. IE huge mess when you get past the restriction. I've had both the flexible lines and tank clogged recently with a black goo. I'm wondering if the tank is being "cleaned" by the new ULSD?

Oh- I just thought of this- Once the tractor gets to bogging down, can you seen if the fuel filter housing is draining empty? If you see that the filter housing is not completely full, this might also give you good power for a few minutes, then starving.

Cooling system problem typically give you a little more seat time before they over heat. Except for a completely closed thermostat. If it is closed, then the upper raidator hose and raidator would be cold and engine hot. And I think your guage would peg to Hot.

Keep us posted on what you find...

 

[Smokin Diesel]

Running hot from a lean condition is a gas engine issue, not a diesel. Since a diesel engine governor adjusts power/rpm by the quantity of fuel being supplied by the injector pump (not fuel and air), symptoms of a filter or a supply line restriction would be similar to simply throttling down. Overheating would not be a symptom.

I'd hate to say it, but KennK might be on to something. Especially since it happened after the fill-up.

Or on the flipside, it could be a stuck injector and too much fuel. How's your oil level?

 

[npaden]

Oil level is fine. After changing the filters and cleaning the radiator it was bogging down without running unusually warm. I think the bogging down and running warm seem to be two different issues and after cleaning the radiator really good it doesn't seem to be running warm anymore although I only ran it about 10 minutes.

I'm going to buy some more fuel from a different place but it was nearly completely out of fuel before I filled it up and it has run for a couple hours since then (although not very well for some of that time) and I've actually burned through about 5 gallons of fuel so I seriously doubt it could be a mix up between gas and diesel, especially since it runs so well initially then starts bogging down as it warms up.

I've looked over the parts diagrams for any check valves or anything that would be likely culprits for clogging and don't see any. I didn't see any extra inline filters added anywhere either. There were a couple hoses that seemed to be cracked and worn and I'm going to replace them but they didn't appear to be clogged at all.

I'm still pretty stumped. It seems like it has to be a fuel delivery issue. But finding the culprit isn't turning out to be very easy.

 

[john_bud]

I know your mech said to use compressed air. I do that too, but every 3-5 air blow out, it gets a water hose (not pressure washer!!!!) cleaning. There is still a massive amount of seeds, dirt and other stuff that comes out every time. And it runs much cooler after doing it. May not be your issue, but maybe it can help.

jb

 

[number two]

Possibly a clogged fuel tank cap vent,making it harder to pull fuel from the tank? Might be worth a try to run it a bit with it removed or real loose.Hey,worth a shot.

 

[RobJ]

Air flow restrictions can also cause oil mist to be sucked in from the crank past the rings into the combustion chamber, maybe thats where the little hint of blue smoke is coming from? Good luck with it.

Larry

Just wondering where you picked up this symptom.

 

[RobJ]

I
I checked her over and let her idle awhile and when I went to shut her down the key wouldn't turn her off. That means that I blew a fuse but that's an easy fix.

Check this out further. If you have a gravity feed system as mentioned fuel should freely flow if you open a nut.

The overheating and bogging may not be connected. My L runs 160 which is what the thermostat opens at. When mowing crap I'll let it get up to 190 before I'll stop and clean out the radiator. But it never effects the power.

If it's not missing then there probably isn't any air getting in the system. If it's starving for air, you'll see the hose connecting the intake to the filter canister start to collapse.

Good Luck!
Rob

 

[backdoor]

The fuel cutoff valve directly attached to my fuel tank got clogged once with what looked like mud. The line from the cutoff to the filter was fine. I changed the filter, cleaned the cutoff, and everything was fine. I didn't have a heating problem, just a weak tractor. I would check the new fuel filter carefully for evidence of water. Maybe even take the fuel line from the tank to the filter off and drain some fuel from the tank into a large bucket where I could see if any water was present.

 

[npaden]

Well, I messed with all the fuel lines and put some more diesel in tonight.

I ran it for 30 minutes pulling the disc in 5th gear and wasn't sure what I had done, but everything seemed to be working great. No smoke, pulling hard, digging deep, back to being my old tractor.

Then it started bogging down again.