Kubota L4150 white smoke, no start

thepumpguysc

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Aug 8, 2018
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Sunny South Carolina
How does this thing shut off?? is it an electric shut off, meaning it shuts off w/ the key switch??
or is it a pull cable??
IF its an electric shut off & it runs for a few seconds.. Take the shut off solenoid OFF..
That will eliminate anything electrical shutting the system down..
 

AlexS

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L4150
Oct 16, 2018
29
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Goldendale, WA USA
The no throttle response would mean that either the injection pump is not installed right, not engaging the governor and throttle linkage or again the pump is bad.
The injection pump was just rebuilt and tested a couple weeks ago. I will have to look at schematics on the linkages. The mechanic that helped me do the swap is no longer available to help
 

AlexS

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L4150
Oct 16, 2018
29
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0
Goldendale, WA USA
How does this thing shut off?? is it an electric shut off, meaning it shuts off w/ the key switch??
or is it a pull cable??
IF its an electric shut off & it runs for a few seconds.. Take the shut off solenoid OFF..
That will eliminate anything electrical shutting the system down..
It has a manual pull fuel shut off as well as a fuel solenoid to shut off fuel. Solenoid is working correctly and manual pull lever is in and not stopping fuel flow. Going down this morning to pull a couple parts and look at diagrams for linkage of the governor and throttle linkage
 

North Idaho Wolfman

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You need to pull the plate off the side of the block just below the injection pump and see if the rack is engaging the governor linkage.
As always pictures of what you see in there will help.

If that reveals no issue then you will need to pull the plate on the front with the throttle linkage.
 

AlexS

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L4150
Oct 16, 2018
29
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Goldendale, WA USA
You need to pull the plate off the side of the block just below the injection pump and see if the rack is engaging the governor linkage.
As always pictures of what you see in there will help.

If that reveals no issue then you will need to pull the plate on the front with the throttle linkage.
Found one more problem. Starter spring on governor was stretched out and not opening fuel rail on IP. Fixed, now getting darker smoke. Guessing I need to bleed more. What do the shops use to bleed injector lines and if cranking, how long do they take to clear. Also going back to throttle linkage, do both the front springs on governor just hook onto the narrow long slot on arm?
 

rbargeron

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As others have said, a compression test is essential, especially with the symptoms its showing. An engine that has not run in a while may have some weak cylinders. A 5-cylinder may have only one or two that get up in the high 300's it usually takes to fire.

An entry-level compression tester like this will work - it has an adapter for the glow plug holes.

For bleeding, there's a helpful discussion for Kubota engines. Bleed one line (injector end) at a time, use the decompression feature for easier cranking.

For mild cases of air in the lines the vent valve on the main pump can purge excess air enough to start.

Once it is running the rings may free up a little and and compression/starting should improve. Good luck, Dick B.
 
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AlexS

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L4150
Oct 16, 2018
29
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Goldendale, WA USA
As others have said, a compression test is essential, especially with the symptoms its showing. An engine that has not run in a while may have some weak cylinders. A 5-cylinder may have only one or two that get up in the high 300's it usually takes to fire.

An entry-level compression tester like this will work - it has an adapter for the glow plug holes.

For bleeding, there's a helpful discussion for Kubota engines. Bleed one line (injector end) at a time, use the decompression feature for easier cranking.

For mild cases of air in the lines the vent valve on the main pump can purge excess air enough to start.

Once it is running the rings may free up a little and and compression/starting should improve. Good luck, Dick B.
Compression on rear problem cylinders are 65 to 110. Front 2 are 270 and 310. Now I need to figure out how to correct this problem. Researching to see if its rings, valves or what? Glad I finally checked pressure and appreciate everyones help so far. I know enough to be dangerous and I am on a limited income. That is why I am doing this myself as opposed to paying a shop.
 

D2Cat

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AlexS, you swapped out an engine that had a hole in it and got one with low compression. The person you got it from, had no idea of condition?

With your kind of luck I'd suggest DO NOT waste your money on a lottery ticket!:D
 

Jim L.

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Jun 18, 2014
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I think that before tearing it open, I would measure and record the valve clearances for later. That might be useful information if it later turns out to be any valve issues.
 

AlexS

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L4150
Oct 16, 2018
29
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Goldendale, WA USA
I think that before tearing it open, I would measure and record the valve clearances for later. That might be useful information if it later turns out to be any valve issues.
I did a wet test on compression and it raised compression by 80 psi. Now for the fun part of splittling the tractor again and doing rings and/or more
 

Pau7220

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An engine that has not run in a while may have some weak cylinders.

Once it is running the rings may free up a little and and compression/starting should improve. Good luck, Dick B.
I'm just asking here...

Why?

40+ years doing auto repair and I have never experienced this unless it was stored in a swamp. I recently started a 6-71 Detroit sitting outdoors in a salvage yard on a pallet for over 5 years.... it didn't turn 1 full revolution before it fired.

Did the scrappers get water in the cylinders during pressure washing allowing aluminum pistons and steel rings to do weird stuff? Would a kerosene or sea foam soak help before jumping off the cliff and splitting the tractor again? Sounds like you have nothing to really lose at this point.

Are the valves closing completely? Water down a valve stem can play havoc also. Solvents or penetrating oil can help with that. Hook an air line up to the compression tester hose and listen to where where the air is leaking from... intake, exhaust, or crankcase.

2 cylinders with very low compression next to each other normally is a blown gasket between cylinders. Although, wet testing won't change that much if at all.
 
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North Idaho Wolfman

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I'm just asking here...

Why?

40+ years doing auto repair and I have never experienced this unless it was stored in a swamp. I recently started a 6-71 Detroit sitting outdoors in a salvage yard on a pallet for over 5 years.... it didn't turn 1 full revolution before it fired.

Did the scrappers get water in the cylinders during pressure washing allowing aluminum pistons and steel rings to do weird stuff? Would a kerosene or sea foam soak help before jumping off the cliff and splitting the tractor again? Sounds like you have nothing to really lose at this point.

Are the valves closing completely? Water down a valve stem can play havoc also. Solvents or penetrating oil can help with that. Hook an air line up to the compression tester hose and listen to where where the air is leaking from... intake, exhaust, or crankcase.

2 cylinders with very low compression next to each other normally is a blown gasket between cylinders. Although, wet testing won't change that much if at all.
I've worked on a bunch of kubota engines and and low compression from stuck rings is very common on these, the only thing I can say is that the clearances are very, very tight, and any junk or dried oil will make them stick.
I have a motor here now that didn't have any water in the cylinders but the rings are stuck tight in all the pistons, and soaking them, in just about everything, has done nothing to free them up, ended up just getting new pistons and rings for it.
 

rbargeron

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I'm just asking here... Why? ...........Did the scrappers get water in the cylinders........
Used engines for resale can be vulnerable to water damage. The scrap yard pictures and the ad wording hold some clues.

The ad said injectors and valve cover etc were not included so it may have spent some time opened up. If rain gets in, it can start rusting the rings to the cylinder walls.

Sometimes a good honing and new rings will get it running so you can then figure out if the rest of the machine justifies a full rebuild.

The L4150 was a very robust model with high build quality, usually worth some repair effort. Good luck, Dick B
 
Last edited:

North Idaho Wolfman

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Used engines for resale can be vulnerable to water damage. The scrap yard pictures and the ad wording hold some clues.

The injectors and valve cover etc were not included so it may have spent some time opened up. If rain got in, it can start rusting the rings to the cylinder walls.

Sometimes a good honing and new rings will get it running so you can decide if the rest of the machine justifies a full rebuild.

The L4150 was a very robust model with high build quality, usually worth some repair effort. Good luck, Dick B
100% agree with this assessment.;)
 

Pau7220

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the only thing I can say is that the clearances are very, very tight, and any junk or dried oil will make them stick.
Ok, question answered.

GM's answer to stuck rings on the Caddy engines was an overnight soak with AC Delco X-66 or X-66A. It's actually a digestive cleaner that you don't want on your skin or paint for very long. I would be the guy trying that as a last resort before a tear down.... as I said, you have nothing to lose at this point but a $10 bill.

I saw the pictures also, that's why I mentioned the pressure washing damage. If it is galvanic corrosion caused by water (stored in a swamp), the rings are pretty much stuck forever.
 
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lugbolt

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Oct 15, 2015
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I've worked on a bunch of kubota engines and and low compression from stuck rings is very common on these, the only thing I can say is that the clearances are very, very tight, and any junk or dried oil will make them stick.
I have a motor here now that didn't have any water in the cylinders but the rings are stuck tight in all the pistons, and soaking them, in just about everything, has done nothing to free them up, ended up just getting new pistons and rings for it.
Ring lands collapsed or compressed?

Have run into this a few times. When questioning the owners, it was found that many times some sort of starting aid was used. Gas rag, carb cleaner, ether. And sometimes it's had a hydraulic lock situation. Causes the ring lands to compress ever so slightly and lock the rings to the piston.
 

Pau7220

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L3650 GST, Landpride TL250 FEL w/ Piranha, 6' King Kutter, GM1084R Finish
Aug 1, 2017
785
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Scranton, PA
Ring lands collapsed or compressed?

Have run into this a few times. When questioning the owners, it was found that many times some sort of starting aid was used. Gas rag, carb cleaner, ether. And sometimes it's had a hydraulic lock situation. Causes the ring lands to compress ever so slightly and lock the rings to the piston.
Now that would do it!
 

AlexS

New member

Equipment
L4150
Oct 16, 2018
29
0
0
Goldendale, WA USA
Used engines for resale can be vulnerable to water damage. The scrap yard pictures and the ad wording hold some clues.

The ad said injectors and valve cover etc were not included so it may have spent some time opened up. If rain gets in, it can start rusting the rings to the cylinder walls.

Sometimes a good honing and new rings will get it running so you can then figure out if the rest of the machine justifies a full rebuild.

The L4150 was a very robust model with high build quality, usually worth some repair effort. Good luck, Dick B
I know now what to look for in a used diesel engine. Thankfully the company has been kind enough to right their wrongs with discounts. The unfortunate part is that they said they were ordering rings and a head gasket on Tuesday. It is now Friday and the owner states he did not claim that and was simply looking for a discount for me. I am on a time frame to get this out of my neighbors shop so he has his space back to put equipment in for the winter. The company knew this. Just ordered ring set myself and gasket has to be expedited from Japan. I know now not to deal with this company and should have just rebuilt my original motor. That would of been half as expensive and half the time involved. Unfortunately when I started this project I knew little about diesels. I have learned a great deal throughout this process. Appreciate everyone's help getting me through this ordeal.
 
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AlexS

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Equipment
L4150
Oct 16, 2018
29
0
0
Goldendale, WA USA
A little update on this expensive used motor that ran at removal and was sold to me this way. 4 out of five pistons are broke between rings. Waiting to here back from Kubota to see if pistons are available in Japan. None are available in the states... Never trust someones word is the experience I got from this. Lots of learning. Thanks again to all those that suggested compression testing