Kubota Diesel

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Any one here with any experience with a 3 cylinder Kubota ? I got a 721D Grasshopper that won't start.
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JimDawson

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Short of catastrophic mechanical failure a diesel requires 3 things to run, Fuel, Compression, and Timed Injection.

The good news is that a Kubota engine is pretty simple to work on.

Will it fire on starting fluid?

I guess I would start out with the obvious, does it have fuel?

Then is the fuel getting to the injector pump? Is the filter plugged up? Is the lift pump working? Maybe replace the fuel filter (be sure to fill it with clean fuel when installing)

Is the fuel getting to the injectors? Crack open an injector line at the injector and crank to see if the fuel is being delivered.

Is the fuel cutoff working correctly?
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kvt

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Does it have glow plugs, If so does it get power to them to preheat and help start it.
but like Jim said three things, Fuel, Compression and injection timing. Sometimes extras to help start like glow plugs.
Fuel from tank, to pump, pump to injectors, if all that is working
then check compression after that start checking the injection timing.
I wish gas was that simple at times.
 
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Guess I should have started with what I have all ready done.
Upon visual inspection I noticed that the fuel lines had been replaced with 3/8" instead of the ¼" that it came with. Being the wrong size the hose clamps were cinched down till they mushroomed off the back side of the hose barb and were still not tight.
So I bypassed the two fuel filters and pump and set up a gravity feed temp fuel can. Then with fresh fuel I bleed the air screw on the pump and the injectors {While Turning the motor over} till all air was purged from the system. I checked the glow plugs and they were getting 12.5 volts. And air filter is new.
Decal on motor and air filter housing say's "DO NOT USE STARTING FLUID"
Still no start. Light white smoke out exhaust and seems like it wants to start.
In the morning my plan was to remove and bench check the glow plugs.

I will admit up front I'm a gas guy so was wondering if I might have forgot something.
Saving compression check for last because of pre-bent steel fuel lines.
Kubota 005 (Small).jpg
And yes I know the white plastic rod from the fuel solenoid to the pump is broken but it still moves the stop/start lever the right distance.
*****Thanks*********G**********


 

JimDawson

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If you have fuel delivery to the injectors, then I'm going with low compression, bad glow plugs, or a bad injection pump.
 

CluelessNewB

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Unlike my old Perkins (Mr Leaky) my 2 Kubota engines (different models than yours, tractor and boat) absolutely need glow plugs to start. Depending on the temperature 5 to 15 seconds of glow plugs is sufficient. I actually suspect you have a fuel problem and the engine needs a good bleeding. Diesels really don't like any air in the fuel lines. I believe there is an air bleeder circled in yellow below. You may want to find an owners manual for your specific block to verify this. Many can be found online. (I suspect your engine is a Kubota D722 block, here is a link to a marine version of that engine, cooling and exhaust systems will be different but the basic block should be the same: http://www.betamarinenw.com/Engines/Resources/Manual - Beta 10, BZ4#D8E09.pdf )

Kubota3.jpg
 
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kvt

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Glow plugs, Do you have a ohm meter, Check the resistance on each if they are out you should not get a good ohm reading between the lead and the block. Like an open circuit, I have had them burnt out by being held on to long.
Another thing to check is have someone turn it over as you crack the line lose on one of the injectors, does it spray out good. If you do not get a good squirt each time it is supposed to then you have a problem like air in the system, plugged input or something. If getting good flow at the injector connection, and the glow plugs have good resistance, then start looking at something like compression or timing. Had a Mercedes that jumped timing one time. Not fun.
 

jpfabricator

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If I run the 4000 ford out of fuel, the only way I have been able to get her fired up again is to drag it with the pickup.
Put the tractor in high gear and start it rolling then dump the clutch.
After it starts running it usually has to be drug a few more laps around the pasture to purge it completly.

Sent from somewhere in East Texas Jake Parker
 
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