L45 will not run. Possible fuel issue

L35 TBL

New member

Equipment
L35, L45
Dec 17, 2014
10
0
1
NH, USA
I have a L45 with about 900 hours that keeps on dying on me and running rough. This has been going on for almost 6 months, but has been getting worse. I have been trying different things without improvement. Any and all help is appreciated.

Symptoms:
1. It does not die, but sometimes runs rough (RPMs drop and runs rough for a few seconds, but quickly comes back to life) when there is >1/2 a take of fuel.

2. It will lose power and often die when there is <1/2 a tank of fuel. It will start back up without any issues but sometimes only run for a few seconds until I get more fuel

3. I can’t always tell, but it seems like it is worse when going up hill…but I can’t decide on this

There is no black/white smoke and other than running a little rough once or twice an hour everything works fine when the tank is full.

Things I have done:
1. Change fuel
2. Clean filter (it was not dirty). It has the o ring on the filter assembly and on the cup. The spring is also in place. (I had hoped it was something as simple as a missing o ring)
3. Fuel pours out of the bottom of the tank and gets to the filter without an issue. It does come out of the lift pump when I turn over the engine, but I am not sure what this should look like. It spits a good stream of fuel an inch or two for a second… should it be more?
4. I have bleed the fuel system a few times hoping this would solve the issue

There is a small crack in the hose from the lift pump to the bleed valve that I noticed today. The hose was a tiny bit wet so maybe there is fuel leaking from this hose. The way this system is set up I don’t think it would be sucking air, but maybe…

I think my next steps would be:
1. replace the hose with the crack (double this is it, but maybe).
2. replace the lift pump. This is a lower cost thing to replace. Maybe things are running well when the tank is full because the extra pressure helps the failing pump? Does anyone know how much fuel should be coming out of this thing?
3. Pull the fuel injectors and have them tested, but it sounds like Kubota fuel injectors hardly ever fail and this is getting a little over my head.
4. Wait the 3 months and have the dealer come look at it and pay them a stupid amount of money.
 

85Hokie

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I think I would start with your option #1...... cracked hose!
 

fried1765

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Good thought, but the air filters are fine. Pulled it apart from the intake too and that is clear.
Have you onsidered that crud may be in the bottom of your tank, and may be intermittently blocking the tank fuel outlet?
 
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L35 TBL

New member

Equipment
L35, L45
Dec 17, 2014
10
0
1
NH, USA
Consider that crud may be in the bottom of your tank, and may be periodically plugging the tank fuel outlet.
I think this is less likely. I have flushed the fuel a few times now and the fuel pours out of the tank. There was minimal amount of debris the first time I flushed it.
 

Henro

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Replace your fuel filter/filters.

check the fuel filler cap to make sure it vents properly.
 

Russell King

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Jun 17, 2012
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Replace the lift pump is my vote
 
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L35 TBL

New member

Equipment
L35, L45
Dec 17, 2014
10
0
1
NH, USA
Replace your fuel filter/filters.

check the fuel filler cap to make sure it vents properly.
Yes, thank you. I should have said this too. I cleaned the cap and have tried running it without the cap on when having this issue. Didn’t help. Fuel has been replaced and filter is good.
 

Russell King

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L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Jun 17, 2012
5,424
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Austin, Texas
Not sure but probably a few inches to a foot out of end and a full stream the size of the tube inner diameter.

The “runs on full tank” is the indicator that the lift pump is weak.

North Idaho wolfman May come along and comment about the flow with more knowledge than I have about the flow
 

L35 TBL

New member

Equipment
L35, L45
Dec 17, 2014
10
0
1
NH, USA
Not sure but probably a few inches to a foot out of end and a full stream the size of the tube inner diameter.

The “runs on full tank” is the indicator that the lift pump is weak.

North Idaho wolfman May come along and comment about the flow with more knowledge than I have about the flow
Thanks, this is very helpful. If there should be constant flow this must be the issues. I was not sure if there should be constant flow given that it looks like a mechanical bladder pump.
 

JimmyJazz

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B2601
Aug 8, 2020
1,225
746
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Pittsburgh, Pa
This post reads a lot like my first that brought me here almost 2 years ago. My Steiner tractor was behaving similarly. A combination of cleaning a partially occluded fuel line and replacing the lift pump fixed it. Between diagnosing the problem and fixing It was a frustrating experience. Shortly thereafter I bought my new B2601. My first new tractor ever. Its really wonderful not having to constantly worry and fix the thing. And paying for it is not too bad at this stage of my life either. You will get that tractor fixed. Don't despair. If I can do it anyone can. Good luck. Also, consider using algaecide fuel additive moving forward as had been recommended to me.
 
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L35 TBL

New member

Equipment
L35, L45
Dec 17, 2014
10
0
1
NH, USA
Update-Replaced the lift pump and we are running like new. Thank you to everyone that responded!