Oil & Fuel TC45D Fuel Vent Problem

[burtrl]

With the engine running, I removed the return line from the check valve at the top of the fuel tank to see if any fuel was returning to the tank. Nothing came out. I then blew into the line to see if it was blocked. Immediately the fuel level rose at the fuel filter due to whatever fuel in the return line being forced back into the filter by my blowing on the line, indicating that the line was not blocked.

I then removed the top of the lift pump to check for any blockages there. Inside the pump there were no screens to plug up, and everything looked good. The way the pump is designed, fuel cannot flow freely through the pump by gravity or suction. The pump must operate in order to have fuel flow to the injection pump. I cranked the engine over, with the fuel lines to the lift pump off, to see if the pump had any suction on the inlet. There was only a very slight suction. Based on the design of the pump I wasn't expecting a great deal of suction so this seems normal to me.

At this point I figure that I have one of two problems. Perhaps the lift pump is weak and is barely pumping enough fuel to keep the injector pump supplied. This would not explain why the fuel level in the filter keeps gradually dropping. The other possibility is that the fuel supply line is restricted, thereby not providing enourgh fuel to the lift pump. This would explain the dropping fuel level at the filter. I have noticed that when the return line is disconnected at the T fitting, if I open the fuel shutoff valve, the fuel doesn't flow into the filter as fast as I would expect.

So, I think the next step will be to drain the fuel tank and inspect the tank and lines for blockages.

 

[barbqranch]

Can you rig up a coffee can or something, with a nipple at the bottom, which you attach to a fuel line to the pump and fill with fuel. Then you could start the engine and see how it runs.

 

[jinman]

So, I think the next step will be to drain the fuel tank and inspect the tank and lines for blockages.

That's exactly what I would do. Good luck!

 

[RADIUM]

I might have a simple solution for you, if I understand you correctly the fuel is getting low in the sediment bowl while the tractor is running right? If this is the case, the simple answer is change the O-ring at the top of the bowl. It was driving me crazy for a year and a half, my dealer couldn't figure it out said it was normal to be half-full sometimes. He was wrong As soon as I put the new O-ring on no more leak. The bowl stays full give it a try $2.95 I believe. I hope it helps . It's been working great ever since, 450 hours later still not a problem, so every once in a while I buy a new O-ring seal and change it out. Just so you understand I'm talking about the O-ring around the sediment bowl, not the little one around the fuel filter itself, But you should change that occasionally also take care

 

[burtrl]

Radium, that is exactly what has been happening. I've been living with this problem for a couple of hundred hrs. Wasn't too bad at first, but now it gets to the point where the engine sometimes stalls due to lack of fuel. I bleed the air out, and after a couple of hours runtime the fuel level drops to half full again. Thanks for the tip. I will definately look at the o-ring.

 

[RADIUM]

Just a few other things , when you go to change the O-ring, on my 2420 the fuel shutoff valve has three settings one off position, and two on positions try using the other on position and go back and forth with a bucket underneath to let the fuel run out, their might be some junk caught up in that shutoff valve. I assume when you change the fuel filter, You let the fuel run out the sides of the sediment bowl for a few seconds to get the air out of the bowl right? Let it run heavy for a few seconds longer than you usually do and shake the bowl it makes a mess, but I have found many times air is still trapped within the new fuel filter which causes the level to drop a few minutes later while running. What really amazed me that the O-ring would let air in, but no fuel leak crazy take care

 

[jinman]

What really amazed me that the O-ring would let air in, but no fuel leak crazy take care

Me too! I'm especially intrigued because we all know that leaving the ring loosened and turning on the petcock lets fuel leak out to clear the air pocket. Then, if your gasket theory is to hold, as we tighten the ring there is a point where fuel quits leaking out and suddenly air starts leaking in. Just sayin'. . . .:confused3:

If the gasket fixes burtrl's problem, it's the dagnabbit-est thing I've ever heard. It would be the ace-boom fix of the year. . . and I'll humbly apologize for being a skeptic.

 

[RADIUM]

I know it sounds goofy. My tractor suffered the same problems in the first year and a half of ownership dealer took it in for two days, could not solve said it must just be a normal condition and not to allow the tank to get low. The solution came from my brother, who runs a heating and cooling business, he told me about customers furnaces that sometimes lose the oil charge due to the oil ring on the filter housing that was allowing air in. I now have well over 840 hours and never had the bowl half-full or stalling again even with the fuel gauge on nearly empty. We'll have to wait and see if it helps LOL take care

 

[barbqranch]

Air can go through a smaller hole than fuel. Also, it might be that somehow the oring acts as a check valve, just letting air through when there is a "vacuum". I don't know, just guessing.

 

[Ford850]

Air can go through a smaller hole than fuel. Also, it might be that somehow the oring acts as a check valve, just letting air through when there is a "vacuum". I don't know, just guessing.

The check valve theory is what I am guessing too.