L3901 needs engine. What went wrong?

Wesley Strickland

New member

Equipment
Tractor L3901
Oct 31, 2022
4
1
3
Alabama
Long story short. Had my l3901 serviced at local kubota dealer & 10 hours later it needs a new motor. Only has 394 hrs. Run it 3 hours with no trouble. Brought it back to my property bush hogged for 25 minutes or so and it would just die. Did it 4-5 times, let it run a hour with no problems. Let my mechanic( friend look
At it) fuel gauge didn’t work correctly and he assumed it ran out of fuel. Filled back up and would never start again. Took it to dealer and they said the injection pump and injectors was bad from water in the fuel. They performed compression test and said one cylinder had no compression and the other was half. 15k for a new motor. What should I do? Part out - have someone else look at it?
 
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sheepfarmer

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In your efforts to be brief there isn't enough information in a couple of places.

What kind of service?
Who ran it for 3 hours? The dealer? That's unusual if they did.
Did the fuel gauge work before the service? They usually don't work all that great.

When you brush hogged did you check the water separator? Had you added fuel since it was at dealer? Engine dying during work is usually some kind of junk in the fuel tank.
What did your buddy fill it up with? Hope not gasoline....how and when did there get to be water in it?

I have the notion the 3901 has 3 cylinders, how did they come up with those readings?

Something is goofy.
 

Wesley Strickland

New member

Equipment
Tractor L3901
Oct 31, 2022
4
1
3
Alabama
Full service; fluids, filters & cleared a regen code. Bought tractor with 100 hours on it and the fuel gauge did not work but after I got it back from service it was working. How accurate it was I’m not sure. I used it 3 hours with no problems with pto engaged. After getting it back to my property I used it 25 minutes/ pto engaged and it would cut off. Did this 6 or so times. Let it idle for over a hour with no problems. We thought it may be a code or what not. He cleaned the fuel lines drained water fuel separator. Drove tractor up the road and we assumed it ran out of fuel. Still unsure if it was out or just quit. It would not start back up. Bled the lines with no luck of getting it to fire. So I then take it to kubota dealer and they tell me water had ruined my injection pump and injectors. 7k to fix but my motor may be bad and they would do a compression check. Said 1 cylinder had no compression and another had half compression. I’m dumbfound on how this happened. What should I do?
 

sheepfarmer

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L3560, B2650, Gator, Ingersoll mower
Nov 14, 2014
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In the case of fuel running out in a 3901, it is not necessary to bleed lines. By chance did your buddy try to get it to start with ether or something similar?
 

Flintknapper

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L2350DT
May 3, 2022
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Deep East Texas
So you used the tractor for 3 hrs with no problem, then took it in to be serviced?

After service (but before adding any additional fuel) it would run for a short period of time and die? Did this several times?

Then after adding fuel.....would not start at all, correct?

Compression test at dealer showed one cylinder within spec, one at 1/2 compression minimum spec and one with NO pressure?

Dealer claims injection pump, injectors are shot due to water in system (quite possible). Also suggests that the engine needs a rebuild or replacement for the same reason?

Your engine is a 3 cylinder, Common Rail, Direct injection design....I believe. So any significant amount of water contamination could indeed wipe out the whole shebang.

Only question would seem to be: When was the contaminated fuel put in the tank?
 

Wesley Strickland

New member

Equipment
Tractor L3901
Oct 31, 2022
4
1
3
Alabama
So you used the tractor for 3 hrs with no problem, then took it in to be serviced?

After service (but before adding any additional fuel) it would run for a short period of time and die? Did this several times?

Then after adding fuel.....would not start at all, correct?

Compression test at dealer showed one cylinder within spec, one at 1/2 compression minimum spec and one with NO pressure?

Dealer claims injection pump, injectors are shot due to water in system (quite possible). Also suggests that the engine needs a rebuild or replacement for the same reason?

Your engine is a 3 cylinder, Common Rail, Direct injection design....I believe. So any significant amount of water contamination could indeed wipe out the whole shebang.

Only question would seem to be: When was the contaminated fuel put in the tank?
Used tractor 3 hours after service with no problems. Got it back to my house bush hogging and it would cut off 25 minutes in. Kept doing this. No additional fuel was added. Was run out of fuel I assume then filled the tank up. Before the fill up I seen no water in the water separator but after it was filled up I did see water in separator but it never cranked once it ran out. Dealer stated since the injection pump & injectors are shot they would do a compression test & said two of the cylinders were shot. Before it quit/ run out of fuel it never threw a code or knock or anything. It would fall on its face after 25 minutes of running that’s it.
 

jyoutz

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MX6000 HST open station, FEL, 6’ cutter, forks, 8’ rear blade, 7’ cultivator
Jan 14, 2019
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Edgewood, New Mexico
Bad for diesels with glow plugs.
The old school ones don't mind it as much in really cold weather, less is more. Put ether in a diesel with glow plugs and boom.

My opinion
Corey
So it’s bad for any diesel made in the past 40 years.
 

whitetiger

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Remove the radiator cap and check the coolant level, don't just look at the surge tank. Report back with your findings.
 

jyoutz

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MX6000 HST open station, FEL, 6’ cutter, forks, 8’ rear blade, 7’ cultivator
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I use it on my case skid steer, no glow plugs. Works fine, its even stated in the manual how to use it. Not debating, just saying.

Corey
How old is that skid steer? I haven’t heard of anything made without glow plugs in decades.
 

fried1765

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Kubota L48 TLB, Ford 1920 FEL, Ford 8N, SCAG Liberty Z, Gravely Pro.
Nov 14, 2019
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How old is that skid steer? I haven’t heard of anything made without glow plugs in decades.
Perhaps the meaning is that glow plugs though installed, are not being used?
 
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Coreymacc

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Bx 2380
Oct 12, 2022
22
17
3
Onoway,Alberta
How old is that skid steer? I haven’t heard of anything made without glow plugs in decades.
I guess I should clarify , my skid steer is a 1975 vintage 1845 Case. No glow plugs. When i first bought it, the starter was burned out of it, clearly from having to crank the engine for minutes on end in cold weather. Small squirt of starting fluid and she fires up in seconds. I would never use it in anything else for sure.

Corey
 
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lugbolt

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ZG127S-54
Oct 15, 2015
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Mid, South, USA
starting fluid should be banned. It is useless. It is death to a kubota compression-ignition engine. Well maybe not useless but there are other chemicals that work fine, just not on compression-ignition engines. I don't use it on anything, and generally don't need it on anything home or at work. If it won't start, find out why and fix it.

starting fluid in kubota engines often bends the connecting rods and/or breaks the piston ring lands between the top ring and second ring.

water usually won't hurt cylinders UNLESS water enters through the air intake and fills a cylinder (a LOT of water in comparison to water through an injector).

the low compression issue-assuming it was tested properly, may be a simple issue. Or it may not be.

My thoughts are overheating, based on the amount of time it ran before shutting down. 25 minutes is about right for a low load situation, in my experience. Diagmaster will show the events and at what temperature. Won't have a code stored in the meter as I remember.

Regen codes are something I would question. You only get those with a soot level stage 3.5 or higher as I remember. At 4 and 5, the dpf would need to be pulled for cleaning. At stage 5, the engine will idle and that's about it. And that annoying beeper would drive me nuts.