Oil & Fuel Tractor is stalling please help!

[orangeman2009]

Hi, I own a 2004 Kubota M6800 HDC. I'm having an intermittent problem. the tractor stalls after 3 or 4 hours of work. First I thought the fuel filter was plugged and I changed it, it ran fine for a few more hours and the same thing happened. Something I noticed is the fuel sediment bowl level goes down and back up while the tractor is running. Is that normal? There is a small strainer inside the bowl when I take it out and clean it (even though it doesn't look dirty) and bleed the fuel system, the tractor runs fine for 3 to 4 hours and stalls again. I drained the fuel tank and re-filled it with new fuel, the tractor ran fine until about half tank. The problem seems worse when the tank is bellow half for some reason. I'm wondering if its a faulty fuel pump or injector pump. Is it possible that air is getting in the fuel system? Any help would be appreciated. Thank you.

 

[Zork]

Is the tank vent plugged? This would be causing a vacuum and draw down of fuel. If it is consistent at 4 hours I'd check this first. If the pickup tube is deteriorated it may cause air to be drawn at the lower levels.

 

[leonz]

Its either 1. plugged vent in the tank fuel cap
or 2. the fuel line is collapsing.

I would purchase 20 feet of the RACOR woven reinforced
fuel tubing from maesco.com - Mid-Atlantic Engine Supply Corp. to eliminate that as an issue
as the injection pump will create a pressure gradient that will collapse
the inlet fuel hose if it is not a woven reinforced fuel hose.

_________________________________________________________________
Once you go flail you never go back:thumbsup::licking::drool:

 

[keyman1808]

Could be something in the tank that is blocking the flow and when he cleans the bowl the suction is broken and floats away until it floats by and gets stuck over the opening too. Just a possibility but I like the other two reasons better. Also how many fuel filters does your machine have. My little BX has 2. You may want to check.

 

[Zork]

Could be something in the tank that is blocking the flow and when he cleans the bowl the suction is broken and floats away until it floats by and gets stuck over the opening too. Just a possibility but I like the other two reasons better. Also how many fuel filters does your machine have. My little BX has 2. You may want to check.

This is actually a great idea for us all to remember in the future, but since the poster is saying it happens about every four hours I tend to believe it is a vent, or as the other poster commented, maybe a fuel line that heats up and collapses. Back in the 80's I dealt with a vehicle that had a paper dry-gas top (the one under the cap) that was in the tank. The starved fuel issue was so random I thought it was a pump because it could be weeks before the engine quit. I finally got frustrated and pulled the tank and found a paper washer inside. The reason it was a problem is that the fuel pickup tube was only a tube with 1 opening rather than a screen mesh. Whenever that cap was just right it would float over and block the fuel pickup and float away after the vehicle stalled and was off for a given time.

 

[JRobyn]

I had a somewhat similar issue with a L4330. It turned out to be a floating glop of goo in the fuel tank. Despite being religious about fuel treatment in every tank. I had to pull the hose fitting off of the bottom of the tank and blow into the tank to create just a bit of pressure to force the goo out. No problems since.

 

[jusalooking]

Let me stick my nose in, where is doesn't belong, You say stalls, does it just quit in steady or does it slow down and rattle and make all kind of sounds before it shuts down, usually when a fuel line or something gets in the fuel system and plugs it it will slowly stop,not just like you turn the key off, now if it just shuts off right now it sounds electric, Does it have a solenoid for the shut off, it sounds like something is getting hot and breaking down