Repair Kubota

[cpurvis]

When it dies, does it slowly wind down or does it stop abruptly, as it does when you shut it down?

 

[cpurvis]

The reason I ask is, if the engine runs--then dies--and can be restarted, something is restricting the flow of fuel prior to it getting to the injection pump. It would not restart if it had gotten air in the system. If it starts, the injection system is primed.

Since replacing the fuel pump didn't fix anything, something else is restricting fuel flow to the engine. That 'something else' could be, but not limited to:

1. Fuel pickup in the tank
2. Fuel line from pickup to fuel pump
3. Fuel pump replaced
4. Fuel filter
5. Fuel line from filter to injection pump

 

[cambre]

When it dies, does it slowly wind down or does it stop abruptly, as it does when you shut it down?

It slowly winds down. I have never heard of a diesel so hard to bleed. Must still be getting air in system. Thanks for staying with me on this. I had to brush hog my yard last week. No joke.

 

[cambre]

The reason I ask is, if the engine runs--then dies--and can be restarted, something is restricting the flow of fuel prior to it getting to the injection pump. It would not restart if it had gotten air in the system. If it starts, the injection system is primed.

Since replacing the fuel pump didn't fix anything, something else is restricting fuel flow to the engine. That 'something else' could be, but not limited to:

1. Fuel pickup in the tank
2. Fuel line from pickup to fuel pump
3. Fuel pump replaced
4. Fuel filter
5. Fuel line from filter to injection pump

I can start engine and it will run awhile and dies. It will not restart until it sits a while, although it some times tries to start. The line inside the tank looks good, and cannot see any trash in the tank. I replaced all fuel lines. Fuel filters and mechanical fuel pump has been replaced. I know I told you this. I don't know how many people you post to, that's why I repeat.

 

[mikebarber]

I am livin in the old school of Kubotas and don't have a huge library on information to quickly look up configuration numbers and parts I own many Kubota diesel engines and I seem to remember most of them having a "lift pump" located on the side of the block with fuel lines going to and from it and usually there is a priming lever that is part of the pump to prime the system it makes the pump displace fuel when the lever is moved There is usually a small plug or bleeder screw on the injection pump located at least in the top 1/4 of the pump body because air rises If you get lucky and have the old school lever and bleeder on the pump crack open the bleeder and begin pumping Another issue Kubota has is a 3 wire run solenoid 1 wire is ground the other connecte to the starter to actuate the PULL IN COIL and the other wire goes to ignition for the HOLD IN COIL pull in coil is not strong enough to pull the plumger back into the coil so there is a pull in coil to do that the reason for this complexity is to limit the heat generated in the solenoid PULL IN COIL only operates while cranking

1 could be that hold in coil is bad allowing it to start then die when starter is released

2 could be a broken or loose wire in the harness to the solenoid

3 could be a bad keyswitch

4 I have a diesel 450d reelmaster that has a switch that cuts power to injection pump if the hydraulic tank is low

Bought that mower for $100
it has a gang of 5 powered reels that cuts 11 feet wide The guy didn't have a clue and it took a bit for me to figure it out and before people jump on me for taking advantage of someone he picked the price Gary

 

[cpurvis]

It slowly winds down. I have never heard of a diesel so hard to bleed. Must still be getting air in system. Thanks for staying with me on this. I had to brush hog my yard last week. No joke.

I DON'T think it's getting air in the system. If it was, you'd have to go through the whole bleeding process every time it dies. Let me get this straight--When it dies, you don't have to do anything other than let it sit for awhile before you can start it again?

If that's the case, something is cutting off the supply of fuel, not air getting in the fuel.

Can you remove the fuel tube from the tank?

 

[cambre]

I DON'T think it's getting air in the system. If it was, you'd have to go through the whole bleeding process every time it dies. Let me get this straight--When it dies, you don't have to do anything other than let it sit for awhile before you can start it again?

If that's the case, something is cutting off the supply of fuel, not air getting in the fuel.

Can you remove the fuel tube from the tank?

That is correct, it will run 10 or 15 minutes then dies. If it sits for an hour or so it will start and do the same, run and die. I have removed fuel tube from the tank and it looks ok. Looking in fuel tank with a flashlight I see no trash, all very clean. I also ran it with fuel cap off , no difference. When I do loosen the line on the injectors I see real fine air bubbles, or what I think is air bubbles, smaller than a pin head. It does that every time I loosen the lines. Did you understand what mikebarber was trying to say? I guess I will have to load it up on a trailer and take it to the grasshopper dealership where I bought it, I guess I hate to give up on trying to fix it myself. Thanks for help. Also, it puts out black smoke when trying to start it. Clears up after it starts.

 

[cpurvis]

If it starts on its own, the injection system does not need bleeding.

What is happening is the fuel flow to the injection pump is slightly less that what the engine needs to run. You can test this with a small container of diesel to replace the tank. A gallon or two will be plenty. Run the hose from the lift pump to this can and see if it continues running longer than it would with the fuel being drawn from the tank. If it dies, the problem is in the tank. If it doesn't die, the tank is not the problem. Correction: If it does NOT die, the problem IS in the tank.

If it dies again, the problem is somewhere between the tank and the fuel filter. Get an electric fuel pump and bypass the lift pump. If it still dies, check the fuel filter. Is it the right filter? Will it flow fuel?

No, I didn't follow mikebarbers thinking. Your lift pump is mechanical, isn't it? If so, there's no electricity to it to be cut off.

 

[mikebarber]

startup black smoke is normal Have you looked at the run solenoid on the injection pump?? Does it have the 3 wires I spoke of ? I should have gone back and looked I didn't think it ran that long so the solenoid issue is mute in that case Have you put a test light on the power to the solenoid to see if power goes away just before engine dies ??? It could be a delayed safety shutdown Too long of a delay for oil or temp in my opinion Corroded safety interlock that gets weak in that length of time ?? Hook test light to power inlet and watch it you will eliminate electric or fuel issue and only half as many things to check You have a fuel pressure gauge to put in the feed to the injector pump ??? If pressure stays up then u are looking ar injector pump problem if pressure goes to zero (or lower if u have combination pressure / vacuum gauge) then you have a restriction before the injector pump

 

[mikebarber]

"No, I didn't follow mikebarbers thinking. Your lift pump is mechanical, isn't it? If so, there's no electricity to it to be cut off. "

pump might be mechanical but think about how engine runs n stops usually a key switch operation to a solenoid