Kubota M4050

[CalypsoMan]

My tractor started stalling when I was mowing. It happened when I was making turns.
It started up again and then finally it wouldn't start. First, my tractor guy thought it was junk
in the fuel tank or fuel lines because the fuel filter didn't have any fuel in it.
He cleaned the tank and replaced the lines and then said it was the fuel pump.
He replaced the fuel pump (and we replaced all the filters, the oil and the hydraulic fluid). and brought it back.
I put 2 rolls of hay out and it went to stall putting it in the shed. Today, I put a roll of hay out and it died
on the way back. I let it set and came back and it started...and then it died about 100 feet later.
My tractor guy says that it could be a bad check valve in the fuel tank or a bad fuel injection pump.
Any ideas? I appreciate any help.

 

[Dave_eng]

An option is to rig up a temporary fuel supply connected directly to the injection pump thus bypassing most of the fuel system. If the tractor runs OK now you know the expensive stuff like an injection pump is not the problem.
Some sort of a squeeze bottle full of diesel so you can keep pressure on the fuel supply to the injection pump.
Some will suggest trying the unit with the fuel tank cap removed.
Personally I have never found any vent in a cap plugged but it is something else to try.

Put a section of clear plastic line immediately before the injection pump so you can see if fuel is constantly delivered to the injection pump.

Dave

 

[GeoHorn]

Sure sounds like a fuel tank vent is plugged. Yep…loosen or remove the fuel cap and see if the problem goes away.
Your tractor guy is going to be embarrassed.

 

[Tx Jim]

Sounds very similar to an M4900 I owned several yrs ago that engine acted very similar. Local Kubota service manager advised me to check for clogged screen in water separator fuel control valve. I removed the retaining screw that held valve in place, removed valve & located tiny screen which was clogged. I cleaned screen reinstalled valve & engine operating problems were solved.

I agree with GeoHorn that fuel tank could not be venting.

 

[BAP]

First off, it sounds like your “Tractor Guy”, doesn’t really know what he is doing except to keep throwing new parts on it at your expense in the hopes that he gets it right. Definitely, don’t spend money on an injection pump without knowing definitely that it is bad. Follow the suggestions of the previous posters. Make sure you have good fuel flow to the injector pump.

 

[RCW]

Like Tx Jim mentioned, quite a few folks have found a piece of trash or hay in the 90 degree fitting at the entry of the filter/separator housing.

 

[Tx Jim]

IMHO faulty fuel check wouldn't normally allow engine to initially start. Check valve wouldn't cause engine to stop operating after putting out 2 rd bales of hay.

Fuel check valve was designed to keep fuel from draining back to fuel tank when engine isn't operating

 

[CalypsoMan]

Thank you all for your suggestions. I’ll let you know what happens. I appreciate it.

 

[CalypsoMan]

I tried starting it without the fuel cap. It took a little bit to start but I thought it ran better. I didn't go very far and I parked it...shortly after I decided that I need to try it again. It started first try and I drove around a little bit and it stalled again. You can't order the fuel tank or the fuel injection pump from Kubota anymore.

 

[RCW]

I could be way off.

I know you cleaned tank and replaced lines and filters, but I would still sooner suspect a restriction between the tank and filter.

The bowl is not full because something isn’t allowing sufficient fuel to get to it. Of course, IP is after the filter and is getting starved. Otherwise, sounds like it’s doing it’s job when it has fuel to work with….

Just my thought process.

 

[Tx Jim]

You can't order the fuel tank or the fuel injection pump from Kubota anymore.

In lieu of concerning yourself with what ""NEW PARTS can't be ordered"" why don't you check for good fuel flow from tank to injection pump???

Checking for good fuel flow is very cheap price to pay compared to new inj pump to then determine that the replaced inj pump[ wasn't the problem!!!

 

[CalypsoMan]

In lieu of concerning yourself with what ""NEW PARTS can't be ordered"" why don't you check for good fuel flow from tank to injection pump???

Checking for good fuel flow is very cheap price to pay compared to new inj pump to then determine that the replaced inj pump[ wasn't the problem!!!

Thank you. I appreciate it.

 

[whitetiger]

My tractor guy says that it could be a bad check valve in the fuel tank or a bad fuel injection pump.
Any ideas? I appreciate any help.

The fact that your "Tractor Guy" says there is a check valve in the fuel tank is worrisome.

Your tractor has a super simple fuel system, a fuel tank with a shut-off, a hose to a simple fuel filter, a hose to a mechanical lift pump, and a hose to the injection pump.

The fact that there was no fuel in the filter tells volumes about your problem. If the fuel filter and hoses have been replaced, the fuel tank cleaned out and the lift pump replaced, the lack of fuel is being caused by a restriction in the fuel filter head. Did your Tractor Guy clean/blow out the filter head inlet side and the shut-off valve in the bottom of the fuel tank?














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