Jerky throttle

Kubotasidewalkdude · Dec 23, 2017

Hey guys. So the other night I was out for 11 hours doing my regular snow removal with the L3940 HST and after, it started acting really weird. Usually, on flat surfaces or downhill slopes it picks up speed no problem but on uphill slopes it doesn’t do quite as well. On the uphills after my shift with the pedal down, it kind of revved up and down here and there and wasn’t acting right. Got it back to the shop, drove it around the parking lot and the throttle was really jerky. I’d give it a bit of gas, let off and it would immediately jerk rather than ease off slowly. The same thing happened with going forwards and backwards. It also drove forward on its own at that time too, which has never happened without using the auto throttle lever...The throttle cable just got replaced so I know it’s not that. All the fluids and filters were just replaced recently as well too. Anybody ever run into this?

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85Hokie · Dec 23, 2017

Cold - Snow - Cold ......

check air filter, check fuel filters - grease everything?

Kubotasidewalkdude · Dec 23, 2017

85Hokie said:
Cold - Snow - Cold ......

check air filter, check fuel filters - grease everything?

All of them were just replaced. It was oil sprayed and grease was applied where necessary

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85Hokie · Dec 23, 2017

Kubotasidewalkdude said:
All of them were just replaced. It was oil sprayed and grease was applied where necessary

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The surging......has to be FUEL or AIR.....or a injection pump not coming back with the throttle. Something is frozen to cause the problems you are having.

Kubotasidewalkdude · Dec 23, 2017

It just doesn’t make sense how I could plow with it for over 10 hours and then all of a sudden it starts acting up...what would be the reason for it moving forward on it’s own? I had to push in the clutch and put it in neutral so it would stop.

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Kubotasidewalkdude · Dec 23, 2017

I was talking to my old man about this yesterday. It says right on the manual, “Kubota farm tractor”. Lol

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85Hokie · Dec 23, 2017

Kubotasidewalkdude said:
It just doesn***8217;t make sense how I could plow with it for over 10 hours and then all of a sudden it starts acting up...what would be the reason for it moving forward on it***8217;s own? I had to push in the clutch and put it in neutral so it would stop.

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Does it have an EGR valve? Any fuel treatment added?

Kubotasidewalkdude · Dec 23, 2017

I’m not too sure. I don’t know too much about it

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sheepfarmer · Dec 23, 2017

11 hrs is a long time, any chance there was enough blowing snow that it could have gotten sucked into the air intake and froze up the air filter? That would only explain part of the problem. Is it possible to get it warm enough to dry everything out? If the problems go away maybe there was ice on the linkages too.

Kubotasidewalkdude · Dec 23, 2017

I’ve ran it for 14+ hours in -20 degree Celsius weather with no issues before. It has to be an issue with the hydraulics. All of the fluid and filters were changed so I can’t see anything else being the issue. It’s Japanese, it’s a tricky machine lol. I also don’t know much about the forward and reverse in 1 pedal if anybody wants to chime in...

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coachgeo · Dec 23, 2017

Kubotasidewalkdude said:
I was talking to my old man about this yesterday. It says right on the manual, ***8220;Kubota farm tractor***8221;. Lol

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Me and him must think somewhat alike..... was going to say..... "stop acting like a Jerk to it and it may stop acting like a jerk to you".

Kubotasidewalkdude · Dec 24, 2017

So you’ve never heard of this issue before? I went out again last night and went really easy on it and it started doing it again.

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John Lash · Dec 24, 2017

A friend had a Kubota. L series I forget which one. He always had fuel issues with it. It didn't run right and would sputter and stall. He'd change the fuel filter and it would work for awhile.
I happened to be there one time when he was working on it. The fuel filter looked new to me. We looked further and opened a valve that went to the fuel filter, which was removed and no fuel came out. We removed the valve that I think was on a plastic barbed fitting and it had a ball of dirt just before the valve. No dirt could get to the filter, it was stopping right before the valve.
Although it sounds like yours is over revving rather than under.

85Hokie · Dec 24, 2017

Kubotasidewalkdude said:
I’ve ran it for 14+ hours in -20 degree Celsius weather with no issues before. It has to be an issue with the hydraulics. All of the fluid and filters were changed so I can’t see anything else being the issue. It’s Japanese, it’s a tricky machine lol. I also don’t know much about the forward and reverse in 1 pedal if anybody wants to chime in...

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Ok......I'm in the holiday spirit......for just a few minutes

Sheepfarmer is pointing out exactly what I mentioned before......yet you have ignored that.......IS THERE a chance that ice, water..etc got INTO the air filter? Simple question....simple answer - despite "the filters being changed - does not mean that ice cannot screw up the works in the air intake .

AND as far as being Japanese.......sorry to tell you, so are Hondas, Toyotas, Subarus, Lexus etc.....and they seem to make damn fine autos! Kubotas have been around for just a few years.....more like 50! They are the Lexus's of the tractor world.....just in case YOU dont know that.

And as for a tricky machine.........ok, nm...... D2Cat will tell me I am trying too hard......which is true!

and for S & G's ....Coach Geo is being very nice!

The forward and reverse pedal is standard on damn near EVERYTHING that using hydraulics to move! Rather simple.....in your car - you place your hand on a knob.....throw it in "D" .....stop.....place it in "R" ........the same thing is going on with the tractor......except with a foot. The pedal is not the problem. Nor the hydraulics.....the problem is engine related....and more importantly

YOU have a fuel problem......or the air intake is restricted........

ok - this is going to be simple.........

TAKE the air filter system off ......inspect? Everything nice and clean and dry????

Go to the local "auto store" - get some diesel additive for DIESEL FUEL - the kind that takes water out and stops the growth of algae. AFTER doing both.....(add the additive) run it.....

for a while - see if anything improves..........

report back .......

coachgeo · Dec 24, 2017

85Hokie said:
Ok......I'm in the holiday spirit......for just a few minutes....

ok... Bahumbug lol. so did someone not put your stocking out when they hung the rest of them? Are you miffed not having snow to plow yet????

Then again as the saying goes.... "the truth" ... "ain't so comfortable"

Kubotasidewalkdude · Dec 24, 2017

85Hokie said:
Ok......I'm in the holiday spirit......for just a few minutes

Sheepfarmer is pointing out exactly what I mentioned before......yet you have ignored that.......IS THERE a chance that ice, water..etc got INTO the air filter? Simple question....simple answer - despite "the filters being changed - does not mean that ice cannot screw up the works in the air intake .

AND as far as being Japanese.......sorry to tell you, so are Hondas, Toyotas, Subarus, Lexus etc.....and they seem to make damn fine autos! Kubotas have been around for just a few years.....more like 50! They are the Lexus's of the tractor world.....just in case YOU dont know that.

And as for a tricky machine.........ok, nm...... D2Cat will tell me I am trying too hard......which is true!

and for S & G's ....Coach Geo is being very nice!

The forward and reverse pedal is standard on damn near EVERYTHING that using hydraulics to move! Rather simple.....in your car - you place your hand on a knob.....throw it in "D" .....stop.....place it in "R" ........the same thing is going on with the tractor......except with a foot. The pedal is not the problem. Nor the hydraulics.....the problem is engine related....and more importantly

YOU have a fuel problem......or the air intake is restricted........

ok - this is going to be simple.........

TAKE the air filter system off ......inspect? Everything nice and clean and dry????

Go to the local "auto store" - get some diesel additive for DIESEL FUEL - the kind that takes water out and stops the growth of algae. AFTER doing both.....(add the additive) run it.....

for a while - see if anything improves..........

report back .......

Will do. It’s just, we’ve got some snow coming tonight and our mechanic won’t answer. Those are simple things anybody can do. I’ll give it a go!

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85Hokie · Dec 24, 2017

coachgeo said:
ok... Bahumbug lol. so did someone not put your stocking out when they hung the rest of them? Are you miffed not having snow to plow yet????

Then again as the saying goes.... "the truth" ... "ain't so comfortable"

yeah......that's it ....no snow to plow!!!

and the truth.......

that is a figment of one's own lack of intelligence when asking for help from those that try to do so.

sheepfarmer · Dec 24, 2017

Kubotasidewalkdude said:
Will do. It’s just, we’ve got some snow coming tonight and our mechanic won’t answer. Those are simple things anybody can do. I’ll give it a go!

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Good for you! I am hoping you have a dry place to work. I find it scary to attack some of these things, for fear that if I get it apart I wont be able to get it back, decrepitude has set in in my hand joints. But it is very rewarding when it's done. If you get stuck come back with specific questions and someone will help you.

Even though on a holiday weekend you couldn't get a new air filter, some are designed to be washed dried and reused, you could take yours in the house and let it thaw out and dry if needed.

Snowing here now...

D2Cat · Dec 24, 2017

Are you sure you have clean fuel with no water in it? If you have work you have to get done, you might drain the fuel and replace with fresh fuel. Save the drained for future use if fuel is not the problem.

Kubotasidewalkdude · Dec 24, 2017

It has to be a hydraulic issue somewhere. The spreader on the back also won***8217;t lower or raise now. Also, turns out I don***8217;t have to work now! Frack yeah, the way Christmas Eve should go.

Mod edit! Watch the language!!!!
And Merry Christmas.

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