engine stalls when engaging hst

Andy Wolke

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Feb 17, 2014
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Smithtown, NY
On a kubota L2800 hst 4x4 So far I have changed the fuel filter bleed the injector lines using the bleeder and doing it as decribed in the book by opening the bleeder and then starting the engine for thirty seconds and shutting down the engine and closing the bleeder. I have also bleed the injectors one by one while the engine is running and got a good stream of fuel from each injector.

The engine wants to stall when engaging the hst but not when you put a load on it with the hydrolics.

Any help would be appreciated. Andy
 
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friesj1

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Feb 17, 2014
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brandon manitoba canada
On a kubota L2800 hst 4x4 So far I have changed the fuel filter bleed the injector lines using the bleeder and doing it as decribed in the book by opening the bleeder and then starting the engine for thirty seconds and shutting down the engine and closing the bleeder. I have also bleed the injectors one by one while the engine is running and got a good stream of fuel from each injector.

The engine wants to stall when engaging the hst but not when you put a load on it with the hydrolics.

Any help would be appreciated. Andy
I have the exact same problem this weekend. L3540 with just 600 hours & professionally serviced last summer. Starts quick & revs to 3000 rpm w/o any sputtering or smoke. But as soon as HST pedal engaged, it stalls. Thinking one of the built-in safety shut-offs?

I found that the safety switch under the seat was frozen open. A minute with a propane bottle careful not to overheat and a couple soft taps freed it up and back to work.
 
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BAP

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I am sure you made sure the brake was off. Might check under the tractor to make sure there isn't snow packed up under there cause the various linkages not to move properly releasing the brakes all the way. The other thing is to check that snow isn't frozen around the driveshaft keeping it from turning. Also check your air cleaner if you haven't to make sure it isn't dirty or even have snow in it from sucking it up.
 

quazz

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I have the exact same problem this weekend. L3540 with just 600 hours & professionally serviced last summer. Starts quick & revs to 3000 rpm w/o any sputtering or smoke. But as soon as HST pedal engaged, it stalls. Thinking one of the built-in safety shut-offs?
This happened to me and I knew it was some sort of safety thing so eventually I looked under the seat and the safety switch arm had slipped outside the stop on the seat. This may not be your issue but it was mine.
It took me 3 beers to figure it out.
 

North Idaho Wolfman

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I'm going with bad, frozen, or misadjusted seat switches!;)
 

Andy Wolke

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Feb 17, 2014
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Smithtown, NY
The tractor has been parked inside and this problem comes and goes it seems like a fuel problem. I have also changed both primary and secondary air filters. The engine runs at 3000 rpms until you step on the hst pedal and then it dies out.
 

Dan_R_42

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I'm going with bad, frozen, or misadjusted seat switches!;)
I'm going to agree with Wolfman on this one. I would rule out all the safety switches with a meter or test light before I would start tearing into a fuel system issue.
 

Andy Wolke

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Feb 17, 2014
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Smithtown, NY
If it is a safety switch isssue it must be the nutural switch on the hst. If it was the switch under the seat I don't think the tractor would start.

Thanks guys for all your input.
 

skeets

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Yup they will start with out you being on the seat
 

SteveF

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This happened to me... It took me 3 beers to figure it out.
Dayumm, it would a taken a six pack for me... lol

Skeets is right... it will start without you being in the seat. But, if started and you stand up and hit the pedal, it will shut off. Sounds a lot like your situation.
 

Billdog350

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Andy, you have it backwards. The neutral switch on the HST IS working BECAUSE when you move that pedal it stalls the tractor. The seat (or sometimes the PTO) safety switch is likely your issue. I've seen both the PTO and seat switches cause lots of issues. Its a known problem on Kubotas, especially ones stored outside.
 

Andy Wolke

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Feb 17, 2014
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Smithtown, NY
Well first I'm going to get a six pack and then I'm going to check those safety swiches first the one under the seat and then if that don't work the PTO swich. I'll do that first thing tomorrow morning.

I'll let you know how I make out. Andy
 

quazz

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Well first I'm going to get a six pack and then I'm going to check those safety swiches first the one under the seat and then if that don't work the PTO swich. I'll do that first thing tomorrow morning.

I'll let you know how I make out. Andy
I would bet my mother in law that it is the seat. I'm not sure so I don't want to risk anything I care about LOL
 

jkidd

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Nov 26, 2023
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I'm going to agree with Wolfman on this one. I would rule out all the safety switches with a meter or test light before I would start tearing into a fuel system issue.
I just joined this board after I had the same problem. My 3.5 hour L3902 was starting fine, reving up fine, but would die as soon as I engaged the HST. It has been very cold here lately. After reading the posts I took a hot air gun to the sensor assembly under the seat and now it is running fine. Thanks to all for the help.
 
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