Kubota wont start

Avery

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kubota
Feb 19, 2024
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California
I have a kubota L345 v1500 engine. Turns over fine but won't start. Put a new fuel pump on so I'm getting plenty fuel to the injector pump. Opened the bleeder valve made sure there was no air. So I cracked open the line at the injectors- how much pressure should there be? it doesn't seem like a lot, I turned it over with the compression release in open position When I close it it turns over with alot of black smoke but no starting. I'm getting power to the glow plugs. I'm not much of a diesel mechanic. It acts like a gas engine when its flooded.

In response to N. Idaho Wolfman,, I bled the injector lines for a long time and didn't help.. Could this be a fuel injector pump issue>? Could the glow plugs be the issue?
Thanks
 
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North Idaho Wolfman

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Sounds like you just need to bleed more air out of the injector lines.
There is no pressure when you open the lines, and just a small amount of fuel per injection cycle so it takes a long time to bleed them.
 

Avery

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Have tried with the throttle wide open . with the nut cracked open at the injector not much diesel coming out Thanks for the help
 

Dave_eng

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I have a kubota L345 v1500 engine. Turns over fine but won't start. Put a new fuel pump on so I'm getting plenty fuel to the injector pump. Opened the bleeder valve made sure there was no air. So I cracked open the line at the injectors- how much pressure should there be? it doesn't seem like a lot, I turned it over with the compression release in open position When I close it it turns over with alot of black smoke but no starting. I'm getting power to the glow plugs. I'm not much of a diesel mechanic. It acts like a gas engine when its flooded.

In response to N. Idaho Wolfman,, I bled the injector lines for a long time and didn't help.. Could this be a fuel injector pump issue>? Could the glow plugs be the issue?
Thanks
A word of caution, never use Quick Start, Either or the like.
Are you bleeding one injector line at a time. In my experience this has helped on my old tractor. However NIW and D2Cat are the experts.
Dave
 

GeoHorn

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Yep…NO STARTING FLUID! …unless you want to risk bent conn-rods etc.
 

Avery

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kubota
Feb 19, 2024
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California
Did you charge the glow plugs?
I know I'm getting power to the glow plugs. The temperature outside is in the low 60's. Tractor has always started, sometimes with a little effort. I've been cracking open injector line individually at the injector. Don't see any air or much fluid coming out. Should I put in new glow plugs ? Thank all of you for your support
 

fried1765

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Kubota L48 TLB, Ford 1920 FEL, Ford 8N, SCAG Liberty Z, Gravely Pro.
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I know I'm getting power to the glow plugs. The temperature outside is in the low 60's. Tractor has always started, sometimes with a little effort. I've been cracking open injector line individually at the injector. Don't see any air or much fluid coming out. Should I put in new glow plugs ? Thank all of you for your support
Low 60's OAT should really not require glow plug use,......but some diesels....maybe!
 

Henro

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Regarding the fuel in the lines between the injector pump and the injectors, is it fair to assume that, since only a small amount of fuel is injected each time, that the injector pump by design only pushes the amount of fuel into the line that is needed to force an equal amount of fuel out of the injector into the cylinder?

I mean, it seems reasonable that the injector pump would only inject the amount of fuel needed into the line that equaled the amount of fuel that should be pushed through the injector into the cylinder, to maintain whatever RPM the governor is looking for. So it probably takes longer than one would imagine to bleed air out of the lines between the pump and injectors.

Obviously I don’t know, but during start up the injector pump might put out whatever its maximum is by design. I take it this is why the Wolfman said the pump doesn’t put out that much, so it takes time to bleed all the air out of the lines between the injector pump and the injectors. And why D2Cat mentioned it sometimes helps to have the throttle opened full when you’re bleeding the lines to the injectors.
 
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Avery

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kubota
Feb 19, 2024
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3
California
Regarding the fuel in the lines between the injector pump and the injectors, is it fair to assume that, since only a small amount of fuel is injected each time, that the injector pump by design only pushes the amount of fuel into the line that is needed to force an equal amount of fuel out of the injector into the cylinder?

I mean, it seems reasonable that the injector pump would only inject the amount of fuel needed into the line that equaled the amount of fuel that should be pushed through the injector into the cylinder, to maintain whatever RPM the governor is looking for. So it probably takes longer than one would imagine to bleed air out of the lines between the pump and injectors.

Obviously I don’t know, but during start up the injector pump might put out whatever its maximum is by design. I take it this is why the Wolfman said the pump doesn’t put out that much, so it takes time to bleed all the air out of the lines between the injector pump and the injectors. And why D2Cat mentioned it sometimes helps to have the throttle opened full when you’re bleeding the lines to the injectors.
I've tried bleeding it a whole lot trying to get air out but I don't see any air. Guess I'll try it again, I do try it with the compression release engaged trying to get the air out. Then I disengage it and leave the glow plugs on for a while, nothing happens just smoke coming out of the exhaust. Thank you
 

GreensvilleJay

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re: I know I'm getting power to the glow plugs.

OK, did you measure the voltage on a glow plug ? That is not the proper test to confirm you have POWER at the plugs. Quick test, point an IR gun at each plug to see if it's HOT after 30 seconds of 'preheat'. The proper test is to measure the current at each glow plug.
 

Avery

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kubota
Feb 19, 2024
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California
re: I know I'm getting power to the glow plugs.

OK, did you measure the voltage on a glow plug ? That is not the proper test to confirm you have POWER at the plugs. Quick test, point an IR gun at each plug to see if it's HOT after 30 seconds of 'preheat'. The proper test is to measure the current at each glow plug.
re: I know I'm getting power to the glow plugs.

OK, did you measure the voltage on a glow plug ? That is not the proper test to confirm you have POWER at the plugs. Quick test, point an IR gun at each plug to see if it's HOT after 30 seconds of 'preheat'. The proper test is to measure the current at each glow plug.
i don't have a ir gun but i will get one thanks
 

Dustyx2

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Haven't seen it mentioned but make sure your battery is charged and it's spinning the engine over fast.
 

Avery

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kubota
Feb 19, 2024
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California
Battery charged , engine spinning over fast with the compression release engaged. I opened the nut near the injectors again getting little squirts of fuel out starting with the longest line from the injector pump. Shutting the nut off while the engine is still spinning to make sure there is no air. Released the compression release and ran a jumper wire to the glow plugs and they got so hot I couldn't touch them. Turned the engine over and just a bunch of black smoke and no start. I'm planning on get an IR gun tomorrow. How hot should the injectors be? How bout if I pull the tractor down the driveway in gear? Would that make a difference? We have a Kubota dealer in town, thinking about taking it in but all the mechanics are younger than the tractor, I'm appreciative of your help.
 

North Idaho Wolfman

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Has it ever run for you?
If it has, did this just happen or has it not run in a while?

It's sounding like you have bad injectors.
Black smoke is indicative to over fueling.
I would pull all t6he injectors out and then follow this:

Attach one line to the injection pump outputs off to the side of the engine.
Attach a injector to the line losely top bleed air out.
Crank till air is out then tighten injector.
Now DO NOT put your hand under the injector, use a piece of cardboard a ways away from the injector to see the spray.
Crank the tractor and you should get a pop and a very fine mist of fuel.
If it does a heavy spray or dripping fuel, it's a bad injector.
Do this for all the injectors.
If any are bad then Just have them all rebuilt.
Do not buy injectors off eBay, Amazon, Fridays parts, or really any other seller as there is a rash of bad injectors being sold.
If you don't have a local fuel injection shop to rebuild them, send them to these guys:
Oregon Fuel Injection

If your not getting any of the injectors to pop, try a different output port on the injection pump, if that works, pull the pump, remove and save all the shims under the pump and Take or Send the pump to be rebuilt.

If none of the ports on the pump will POP a injector, are you sure you don't have the fuel stop pulled and you sure you are feeding fuel to the injection pump?
 
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Dustyx2

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Are you sure your air intake isn't blocked? Have you changed filters, both air and fuel? I had a Deutz diesel in a Miller welder that wouldn't start with black smoke out the exhaust. Wound up changing the fuel filter
fixed it. I went after the air filter first but that didn't help. Really didn't expect the fuel filter to help but it fired right off after changing it. Still a mystery to me why that fixed it.
 

Avery

New member

Equipment
kubota
Feb 19, 2024
18
1
3
California
Has it ever run for you?
If it has, did this just happen or has it not run in a while?

It's sounding like you have bad injectors.
Black smoke is indicative to over fueling.
I would pull all t6he injectors out and then follow this:

Attach one line to the injection pump outputs off to the side of the engine.
Attach a injector to the line losely top bleed air out.
Crank till air is out then tighten injector.
Now DO NOT put your hand under the injector, use a piece of cardboard a ways away from the injector to see the spray.
Crank the tractor and you should get a pop and a very fine mist of fuel.
If it does a heavy spray or dripping fuel, it's a bad injector.
Do this for all the injectors.
If any are bad then Just have them all rebuilt.
Do not buy injectors off eBay, Amazon, Fridays parts, or really any other seller as there is a rash of bad injectors being sold.
If you don't have a local fuel injection shop to rebuild them, send them to these guys:
Oregon Fuel Injection

If your not getting any of the injectors to pop, try a different output port on the injection pump, if that works, pull the pump, remove and save all the shims under the pump and Take or Send the pump to be rebuilt.

If none of the ports on the pump will POP a injector, are you sure you don't have the fuel stop pulled and you sure you are feeding fuel to the injection pump?
Yes, I've had this tractor 20 plus years. I replaced some gears in it this winter. I have a hydraulic problem with the loader, parked it in the back of the barn for bout a week and it wouldn't start. Just a bunch of black smoke. Last summer it was smoking alot, put some lucus injector cleaner in the fuel and smoked alot then cleared up. It had a lot of blow by coming out of the vent tube . Maybe your right about the injectors. I'll take them out and have them rebuilt. I live in Grass Valley Ca. Maybe in sacramento theres somebody that can rebuild 'em. If not I'll ship them to the place you recommend. Thanks, I'm learning alot from this forum.
 
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