"Run away" Kubota engine

ShaunRH · Mar 30, 2015

I'd also say stuck fuel injection pump, but you can test a couple of things to verify that.

If you put a fuel shutoff valve (or use a set of vise-grip style hose clamp) on the line before the lift pump or sediment bowl, that will shut off the fuel. If it continues to run-away or even run, you are getting oil into the chambers somehow (if it's turbo-charged, you could have a leak in your oil seals on the turbo).

If cutting off the fuel kills the engine, then your rings (and if you have it, turbo) are good. At that point, something is opening up the system wide open. Disconnect the control linkage that runs the injection pump. Make certain it is pulled back to idle position AT the pump. If it runs away, then your issue is with the pump, it's stuck wide open. If it idles, then the issue is with your controller.

Admittedly, I don't know how mechanical or electronic the control are on your motor, but the principles I described above work to isolate systems and that is what you need to do.

Daren Todd · Mar 30, 2015

That ticks me off when company's do that. If the motor meets the warranty requirements. Being under the hours and years, then it should be covered, no matter how many owners it's been through

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rentthis · Mar 30, 2015

The thing that I most want Kubota to do is to establish a formal technical services operation. Most of the time (almost always) they refer you back to the dealer. My dealer does a great job for me but sometimes they just don't have the answer. This runaway engine seems to be a case of just that. This forum comes really close though.

North Idaho Wolfman · Mar 30, 2015

Does it smoke when it runs?
Is it black or is it blue?

707pc50 · Mar 31, 2015

Yeah it was smoking quiet a bit. I want to say black but I should run it again to confirm. Which if black I would assume is diesel powered not oil right? We were running it on a jerry can of fuel since the gen set doesn't have a onboard tank and we pulled the intake line out of the can so we thought it was running on oil since it stumbled along for a few minutes after that while we were trying to cut the air off but I'm thinking how long could it run at really low rpm on the fuel in the system? So maybe it was running on diesel not engine oil? Anyway I'm gonna do some more testing on it today and see what I can figure out

nickelplated5s · Mar 31, 2015

North Idaho Wolfman said:
Does it smoke when it runs?
Is it black or is it blue?

2500 hours on a 2014 in Arcata? If it doesn't smoke the previous owners do

707pc50 · Apr 1, 2015

nickelplated5s said:
2500 hours on a 2014 in Arcata? If it doesn't smoke the previous owners do

Bought it in Sacramento so...

Anyway Kubota and hardi said they will not cover any repairs under warranty and I should find a diesel mechanic, so I guess I'm stuck trying to figure it out or paying someone to do it. Bummer.. I'll let yall know how it goes

707pc50 · Apr 1, 2015

Apogee said:
We were typing at the same time.

If the rack in the injection pump is stuck, either due to the rack itself or a governor problem, one could still have fuel even though one thinks the fuel is shut off.

Can you explain how this occurs to me? Could we still have fuel if the fuel line was disconnected and sucking air? somehow running off fuel in the line and the filter while not air-locking somehow? I guess the thing is rated at .1 gal/hour burn at no load so it should be able to lug along for a while on fuel in the system? In my experience these things die pretty quick normally when the fuel line is disconnected? thanks-

Orange Turbo · Apr 1, 2015

Apogee said:
We were typing at the same time.

If the rack in the injection pump is stuck, either due to the rack itself or a governor problem, one could still have fuel even though one thinks the fuel is shut off.

A friend rebuilt one for a wood chipper, I just happen to come along as he was first firing it. It started right off and revved wide-open, he choke it down by collapsing the intake tube. He said: I got something in the governor wrong! Anyway he took the side off it and changed something around put it back together, took about 15min and fired it up again, and it ran perfect.
Is what I'm getting at, is maybe someone was in it and got something wrong in the governor. "Just a thought".

707pc50 · Apr 8, 2015

Ok here's the update, we still haven't figured it out. Put a ball valve on fuel line, fired it up, started running away again, turned key switch off which for the first time made the engine stumble then it kept running, turned off fuel at ball valve didn't do anything, we cut the air and shut it down.

At this point we decided to do some investigating. Pulled the valve cover, inspected pcv hose, it was dry on the inside.

Nothing to out of ordinary except lots of oil in the intake manifold???

We then pulled the head thinking something must be wrong there. Nothing obvious just had head pressure tested and everything was good.

Machine shop guy while recommended checking the rings by pouring diesel into block with cylinders at mid way up. Diesel stayed put didn't move around rings.

Any ideas on where to go from here?

Ordered a new head gasket so we're ready to put it back together just unsure since we didn't find anything wrong?

North Idaho Wolfman · Apr 8, 2015

Have you pulled the injector pump?
Have you inspected the governor?
Sounds like the injector pump is not shutting off the fuel, and cutting the fuel off before the injector pump will still allow the engine to run for a pretty good amount of time till it runs all the fuel out of it.

707pc50 · Apr 8, 2015

No we haven't disassembled pump or governor The guy helping me was convinced that once fuel was shut off directly behind the pump it should shut off, but this is kind of what I'm thinking at this point also. Especially if it is just lugging along without any air, probably could run on that fuel in the pump for a while? They say at no load this engine burns less then .1 gal/ hr so I guess it's possible to run a while on a few ounces of fuel??

Anyone have schematic or diagram or tips what to listen look for with governor or injector pump issues?

Thanks for the help.

Apogee · Apr 8, 2015

Based on your "engine stumbled" comment and the fact it kept running, I'm with Wolf in thinking that either the injector rack is stuck or you have a broken or disconnected governor spring.

You don't want to completely disassemble the injection pump. That is better left to someplace like Oregon Fuel Injection. However, you can pull the pump and make sure the rack moves VERY freely. If it doesn't, you've found your problem.

And yes, the engine will run for a while with the fuel in the lift and injection pumps even with your ball valve turned off.

The only other thought that comes to mind is you mentioned early on that you were wondering about valve guides. With the head off now is the time to check them. I don't think they are the issue, but it IS already apart...

Good luck,

Steve

707pc50 · Apr 8, 2015

Yeah the machine shop pressure tested head said everything is good, they are going to put in new valve stem seals since we it apart. Ive never delved into the fuel injection system, I will look around for a diagram or something on line to help me understand it, thanks for the tips.

Apogee · Apr 8, 2015

707,

This should help with basics. The "G" is the generator version. I'd suggest saving a copy:

http://www.k2dt.com/library_files/2278.pdf

For a D1005 exploded parts diagram, go to kubota.com, select the Parts tab, then click on "Illustrated Parts List", accept the agreement, then type in B7500 for the model number. You can choose any of the tractor models that the search returns, but I'd suggest just choosing the first one. The "D" model is the basic 4wd model (not that it really matters). Both the B7500 & the B7510 used the D1005 engine. The build family is different but the engine basics are the same.

Once the menu opens up, on the left click "Engine" then search around for what you are looking for. I'm guessing you will find pics that *should* help under the following entries:

110500 "Fuel Camshaft & Governor Shaft"
120000 "Idle Apparatus"
120200 "Injection Pump"
120401 & 120402 "Governor"
120500 "Speed Control Plate"

THE LEVERS AND GOVERNOR ASSEMBLY ON YOURS WILL BE DIFFERENT. The only way to get the exact exploded diagram and parts list for your engine is to find a Kubota Industrial Dealer/Parts department. They will have the correct exploded diagrams. But hopefully this will at least get you started.

The levers on the pump and governor will be different on your engine because you have the generator model. But, the exploded diagrams will at least give you an idea of how things go together and what should be where.

Finally, here's a link to the Kubota Industrial Site. This will help you find the industrial engine dealer in your neck of the woods:

http://www.kubotaengine.com/

I hope this give you a bit of a start.

Good luck,

Steve

707pc50 · Apr 16, 2015

got it back together and running. determined it was running on fuel while running away, can get it to shut down with fuel shutoff valve and controlling air until it burns fuel in the system. Pulled cover on fuel pump found rack to be stuck. Unstuck it, restarted engine, generator purred normal rpm (actually 1850rpm but at this point i'm not gonna worry about 50rpm when we've been way over this). Shut it down with key switch. Started it again let it warm up, did an oil change, started again and generator RANAWAY again! WTF? Opened cover and unstuck the rack. Started it up and it RANAWAY again. Decided this was going nowhere and I need to use this generator so took it to the dealer.

Today they called and said it needs a new fuel injection pump. I should be getting a price for them do the job soon. what is involved here to do this job? I have a parts motor? can I swap the pump off my parts motor?

thanks

Tx Jim · Apr 17, 2015

I think you can swap IP from parts engine to runaway engine. I think a competent diesel inj pump repair facility could repair the runaway inj pump. Are you quite positive the governor isn't at fault?

Apogee · Apr 17, 2015

I'm also wondering if there isn't a return spring in the system that is supposed to pull the rack back to idle. It could be that the spring is missing and the governor is opening the rack to full throttle and it's getting stuck because it's opening too far.

I'd call Oregon Fuel Injection and chat with them about it before I did anything else. Since it runs fine, I highly doubt you need a new injection pump. Just need to figure out why it's sticking. It might just need to be cleaned.

Yes, your spare pump should work as long as it's from the same model engine and isn't worn out. You might need to adjust the pump timing though. The pump timing is set by shims that sit between the pump and the block.

Please keep us posted on what you learn. This is an interesting one...

Good luck,

Steve

707pc50 · Apr 17, 2015

Yeah fairly positive. The guy who is helping me work on it found that the rack was stuck he forced it free and problem was solved but then it would stick again. Dealer said this can happen if a generator idles for long long periods of time with no load. Something about wearing a groove in the rack which causes it to hang up with lots of no load time.

As for swapping injection pump how do i do this? It seems like the body of the pump is part of the block.

Thanks for the help

Apogee · Apr 17, 2015

I'd recommend taking a look at the exploded diagram. There are four bolts or nuts that attach the pump to the block. They are on the top.

For a D1005 exploded parts diagram, go to kubota.com, select the Parts tab, then click on "Illustrated Parts List", accept the agreement, then type in B7500 for the model number. You can choose any of the tractor models that the search returns, but I'd suggest just choosing the first one. The "D" model is the basic 4wd model (not that it really matters). Both the B7500 & the B7510 used the D1005 engine. The build family is different but the engine basics are the same.

Then just choose "Engine" then "Injection Pump" to see how it goes together.

I've attached the diagram but it's easier to see on the Kubota site. Gives an idea anyway.

Good luck,

Steve

"Run away" Kubota engine

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