3cyl Kubota Diesel need help.

2162 Views 9 Replies 3 Participants Last post by FredM, Nov 26, 2020

Gregincanada

Discussion Starter · Nov 25, 2020

So to sum it up, I ripped this motor out of a magnum light plant and force fed it into an old JD skid steer that had a 2 cyl gas pot that blew up. It ran great all summer and started instantly. Last month while filling in a water line trench it started to stall and then rev back up again. Well it won’t run steady. It struggles to fire up (assuming air in line) then runs for about 30 seconds and just straight up dies. Here is what we’ve done.

Blown out fuel lines
Replaced fuel filter
Checked pick up tube
Tightened all clamps
Removed injection pump and checked springs. All good.
Removed and blown out all injector lines
Removed and cleaned injectors.
Installed injectors outside of engine cranked and watched good spray.
Pulled return line off and placed in a clear jug and ran. Pickup pump primed and squirted maybe 1/8 cup diesel. When running zero return.
Supplied constant power to pickup pump (which was on a timer)
Still same thing, every time. It will be hard to start like your bleeding air. Then it runs and dies after 30 seconds. Racking my brain on this one.

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FredM

· #2 · Nov 26, 2020

No mention of checking the fuel shutoff solenoid, the power supply to the solenoid may be surging and causing the solenoid to shutoff and open and shutoff completely.

Have you checked the glowplugs for your hard starting problem?.

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Gregincanada

Discussion Starter · #3 · Nov 26, 2020

FredM said:
No mention of checking the fuel shutoff solenoid, the power supply to the solenoid may be surging and causing the solenoid to shutoff and open and shutoff completely.

Have you checked the glowplugs for your hard starting problem?.

sorry we had an issue with solinoid at first so we changed it to manual.

glow plugs perhaps. But I think that’s air in the line. Main issue is it shutting off.

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TX MX5200

· #4 · Nov 26, 2020

I had similar issue with my old yanmar..after testing injectors, lines and filters I called an old time diesel mechanic 5 hours away.

He told me to pull ground at both ends, clean and reattach and call him back of no joy.....walla, it was losing ground and shutting down. I got lucky, but worth a try as it's simple and free.

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Gregincanada

Discussion Starter · #5 · Nov 26, 2020

TX MX5200 said:
I had similar issue with my old yanmar..after testing injectors, lines and filters I called an old time diesel mechanic 5 hours away.

He told me to pull ground at both ends, clean and reattach and call him back of no joy.....walla, it was losing ground and shutting down. I got lucky, but worth a try as it's simple and free.

I dunno about a ground as it’s mechanical shut off.

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TX MX5200

· #6 · Nov 26, 2020

Gregincanada said:
I dunno about a ground as it’s mechanical shut off.

So was my Yanmar....my issue was when it lost ground it was shutting down the fuel pump.....it was starving fuel, but cause was shorting ground where neg cable attached to frame. It was tight connection just corroded contact.

On mine I could turn key off and throw it in the dirt and it would keep running til ya pulled the decompress lever

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Gregincanada

Discussion Starter · #7 · Nov 26, 2020

But there is only a pickup pump that is on a timer for about 15 seconds. I did apply power for the full time while it ran for 30 seconds or so. So confused.

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FredM

· #8 · Nov 26, 2020

how secure is the manual fuel shutoff control, you have to look somewhere else, you have done most things that would give you trouble, your fuel shutoff, have a good look at it, check the hoses and seals for air leakage, do you have to bleed the system after the engine stops?, apart from what you have done, the injection pump may need overhauling!!.

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Gregincanada

Discussion Starter · #9 · Nov 26, 2020

Again another thing I did was hold the manual shutoff because that was a thought too

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FredM

· #10 · Nov 26, 2020

Looks like you have been there and done that, have you cracked the fuel tank cap at all, just in case the breather may be blocked, I am not sure if the kubota fuel tank has a strainer at the outlet, have you let fuel run from the tank to check flow, I am running out of options like you.

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