Will not Crank, Fuel issue

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ForsythKubota

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Equipment
B7610
Aug 5, 2024
7
0
1
Forsyth, Georgia
Hello, I have a B7610. I parked it and now it will not start. The engine turns over. I checked the fuel, and I have flow up to the part that I have marked. Can someone please identify and tell me what might be the issue. Thank you.
 

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Henro

Henro

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Most important is that you express what crank means?

Do you mean the engine turns over with the starter but it doesn't start, or do you mean the starter doesn't turn over the engine?

I take it you probably mean the former, but it's important to be specific when you ask a question so that you get answers that will help you solve your issue.
 
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Dustball

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2016 B2650HSDC
Sep 15, 2023
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You have conflicting information.

Diagnosis terms-
"Will not crank" means that the engine will not rotate/turn over. This is usually an electrical issue or the engine is mechanically locked up.

"Cranks but does not fire" means that the engine turns over with the starter but will not fire/run.

I believe you meant that the engine turns over but will not run?
 
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PoTreeBoy

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Mar 24, 2020
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ForsythKubota said:
This is where the fuel stops flowing.
Click to expand...
That's a fuel pump, called a lift pump, very similar to the fuel pump on a '57 Chevy, but smaller.

So, if you pull the short line off that runs from this pump to the injection pump and crank it over, no fuel spurts out? If that's the case, replace the pump. You can probably get one off eBay a lot cheaper than Kubota. This assumes fuel flows freely up to the pump.
 
chris_the_wrench

chris_the_wrench

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Equipment
L3902
Oct 31, 2023
64
21
8
Chinook Pass
ForsythKubota said:
Hey thanks to both of you. I was trying to figure out if it was the fuel pump. From what I understand it is supposed to run when the key is turned?
Click to expand...
Just so we are clear. Thats a mechanical pump that runs off the cam shaft, it will only pump when the engine is spinning(running like normal, or the starter is spinning the engine during the starting process). It wont pump fuel if the key is just turned to the run position.
 
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MOOTS

MOOTS

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MX6000
Jun 27, 2019
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Canton, Georgia
Welcome. Forsyth city or county? I’m close to the county and could give a hand, if needed.
 
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chris_the_wrench

chris_the_wrench

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Equipment
L3902
Oct 31, 2023
64
21
8
Chinook Pass
ForsythKubota said:
Okay I took the short hose off and it shot fuel when I turned the engine. Thank you for your guidance there. What could be the next possibility?
Click to expand...
You 'turned the engine' by engaging the key so that the starter turned the engine, correct? So you are getting fuel to the injection pump? Do those have a fuel solenoid? I believe they do but I will yield to someone who knows that unit better.
 
N3BP

N3BP

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The B7610 does use a key stop solenoid, so it sure does sound like it's not working or stuck. There is a 30A fuse on the muffler side of the engine that should say Solenoid on it. Make sure the fuse isn't blown.
 
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Henro

Henro

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May 24, 2019
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N3BP said:
The B7610 does use a key stop solenoid, so it sure does sound like it's not working or stuck. There is a 30A fuse on the muffler side of the engine that should say Solenoid on it. Make sure the fuse isn't blown.
Click to expand...
And just as an afterthought, fuses do age, and they also do fail overtime, even if there’s not an issue external to them. So if you find the fuse blown, replace it and see what happens. If the fuse doesn’t blow again, and the tractor starts and runs normally, then you probably lost the fuse due to aging.

This doesn’t eliminate other possibilities until after you see the tractor is running again. The fuse could be good and you may have an issue with the fuel cut off solenoid, or something in the related circuitry.

One step at a time…
 
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Russell King

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The above posts are assuming you have a LOT of knowledge about the fundamentals of the tractor’s fuel system.

I am going to assume you know very little about it and explain it in some detail so don’t take it the wrong way please! And to make it worse I have to assume that your tractor has a mechanical fuel system so that could be wrong.

Fuel should flow out of the fuel tank through all lines and lift pumps to reach the injection pump. Then the injection pump pumps fuel to the three injectors that then spray fuel into the cylinder and allows the cylinder to burn the fuel if there is enough compression.

Since you say that it was running and then parked and won’t start I will assume there wasn’t and still isn’t any problem with that system until you try to diagnose other problems.

I also assume that when you turn the key to off the tractor stops running without you doing anything else. If that is true that means you have some electrical solenoid that basically holds the fuel off long enough for the engine to die. In the older tractors there was a mechanical method of getting the fuel flow to stop (a lever or a pull knob). There are two different styles of solenoids to do this with and Kubota has used both types on different tractors.

The solenoid has to operate for the tractor to start and run. Since they are electrical the fuse has to be good and supply power to the solenoid when the key is on. So locate the proper fuse and verify that it is good or replace it with a known good one.

Or first verify that the solenoid is operating properly by looking for it around the fuel injection pump ( not the lift pump). You will need a helper to turn key to on and off to see if the rod of the solenoid is moving. You may have to remove the solenoid to see if it will move. Some of them the case has to be grounded to work.

You can try to physically move whatever the solenoid is attached to to try to get it running. You may have to remove the solenoid to move what is connected to.

Take pictures before you remove anything so you can get it back together the same way.

Good luck
 
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ForsythKubota

New member

Equipment
B7610
Aug 5, 2024
7
0
1
Forsyth, Georgia
Hi there. Sorry I have not replied. Been in the hospital. Long rough week. Thanks Russell for that detailed explanation. No offense taken at all. I appreciate any and all help, and thank you to everyone else. I need a couple of days before I get on the tractor again. I am going to take your advice and try that. When I turn the key off everything stops. No extra levers or knobs. Mine is a B7610 from the later 2000's. Going to try the fuse and then go from there.
 
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