B7510 runaway engine

[Drcarter]

I just bought a 7510 kubota has been running great. Mowed about an hour engine started slowing down ,like runnung out of fuel, looked at gauge showed 1/4 . Turned it off filled with fuel cranked it and engine was running away. Turned key off ,worked throttle, still wide open. So much black smoke, only way i got it to stop was in gear and brakes. Seems very strange, any help would be great. Also thanks for adding me to the group.

 

[North Idaho Wolfman]

Did you fill it with gasoline by mistake?
Did you put fuel in the crank case?

Not trying to rip on you, but stranger things have happened!

VERY VERY Rare for a kubota to do a run away.

The only real way possible on that model is to have severely damaged the governor, which in all my years I've yet to see.

 

[Drcarter]

Thanks for replying, no offroad diesel,and in tank. I have an auto mechanic ,gas, for 40 years . Just really crazy, never seen so much black smoke. Been looking at posts but not sure whats going on. Gonna pull the side covers off today and look around.

 

[D2Cat]

Your clue of "never seen so much black smoke" would suggest you double check the fuel container, to be positive you filled with diesel, not gas.

 

[thepumpguysc]

U might of had an injector blow a tip.?? hence the black smoke..
Def. pull the cover & see if the control rack is stuck..
Good luck

 

[North Idaho Wolfman]

If fuel is clean and only diesel.

Then Injection pump or injectors are about it.

Pull the side cover and see if the rack moves freely.

Then if that moves pull the injectors.

 

[gsganzer]

Check your crank case oil level. If it's grossly overfull, you could be running on oil.

 

[Drcarter]

Crankcase is at full, def off road diesel, did start it again. It is running at full throttle and i have to stall it to shut down. Looked at a few posts,if i take the throttle lever off and the 4 bolts ,take the cover off what shoyld i be looking for? Will anything fall out or spring out? Thanks again. Ps im pretty good on gas but this is out of my knowledge but with your help i am capable.

 

[SidecarFlip]

Actually the best and least damaging way to shut it down (besides the red engine stop knob (if it has one) is starve it for air. Take the air filter housing off to expose the intake runner and use a flat piece of wood or metal to close off the intake. No air, no run.

 

[Drcarter]

If anyone could help me with info on how to remove the platewhere the throttle linkage goes and im gonna pull the pump. Looked on line looks like the pump is easy enough to pull but looks like the linkage plate may have a couple of springs. On the pump seems i need to look for a broken spring on the lifters. Is there anything special to look for when pulling the throttle cover.

 

[Drcarter]

I have anotherthing i noticed,i dont think its running away, just running wide open. Still smokes really bad,
If it wont stop with the switch ,which has power to the solonoid what is the direction i should look? Where should i start. Injectors, pump or rack springs.still runs wide open and wont cut off
Any help would be great

 

[North Idaho Wolfman]

There should only be one spring attached to the throttle plate.

 

[Drcarter]

Thanks wolfman, im gonna pull the plate today ,see what i find thanks. Should i go ahead and pull the pump and look at the lifter springs? Anything else to check closely? Thanks for your help.

 

[GeoHorn]

Might be an ignorant suggestion... but are you certain your hand-throttle linkage isn’t fouled in the open position?

 

[Drcarter]

Pretty sure ,its moving back and forth when i pull and push the lever. But wont shut off with key. It was working greay ran out of fuel and went all to heck.

 

[thepumpguysc]

I know your nervous, but u shouldnt be.. not w/ all this help here..
Pull the plate.. & under it will expose the inj. pump & engine linkage..
Move YOUR throttle up top at the controls & look to see if its moving the pump & engine linkage in the engine/at the pump..
If it is, chances are the problem aint there.. It might be time to pull the injectors..
IF u feel comfortable starting the engine again, loosen 1 line at a time AT THE INJECTOR & retighten to find the cylinder that DOESNT slow the motor down..
Just like pulling a spark plug, the bad cylinder wont change the rpm's..
BTW> u can stop the engine by loosening all the lines AT THE INJECTORS.. no fuel=no run.
SAME w/air.. NO AIR=no run..
Good luck

 

[Drcarter]

I wiil pull the cover in a little and see what we see. Thanks so much.6

 

[Drcarter]

Ok pulled the plate and had a sping hooked to cover also spring lookin in on left hooked both ends. I can see a 3rd spring looks like its screwed in from front it will hit one of the levers. Everything looks clean and the 2 levers move freely but not much movement maybe inch or less. Up top at the pump there is a little slack but no movement.

 

[Drcarter]

Look some more the arm in the back near the pump wont slide and i noticed its all the way back against the stop. Its not against the stop ant front cover . Seems it should slide back and forth, front to rear
Solonoid is clicking and i can see it moving about 1/16 of an inch. Any ideas whats next. And again thanks so much for the help.

 

[Drcarter]

What i meant its back at the stop solinoid. Seems that should push it forward.