Oil & Fuel Sucking air while bleeding fuel lines

[beltfed]

I had the same problem last month and had fuel flowing out all the bleeder screws and injectors. Still couldn't start the engine. Ended up calling the local tractor place and they came out while I was at work. Spend 1½ and fixed the problem. I still don't know what they did, but when I arrived home from work the tractor started. I guess you can call your local service when you are frustrated enough. /forums/images/graemlins/confused.gif

 

[Gatorboy]

<font color="blue"> Is there any chance the fuel flter had a clear plastic cover on it that you did not notice? Like something to keep dust and dirt of the element until installation time? </font>

I don't think so, but I'm definitely going to remove the fuel filter when I go back out there. When I loosen the nut above the filter (which is the first step to pump out the air bubbles), I have diesel flowing out there in a steady stream as I pump the manual fuel pump. Now I'm thinking, maybe there is some blockage -- I'm willing to try anything at this point, for I have already wasted about 10 hours so far.

 

[Egon]

That sounds aggrivating. Starting at the fuel tank apply the [10] theorem to every fitting till you locate where the fuel supply ends.

First I'd probably do is break the connection to the injector pump and see if there is fuel there. I'd also clean out all the lines as perhaps some crud is lying there and will only cause restriction or blockage when there is a movement of fuel.

But as in all tough questions, just like a program, sit down, let your mind follow the flow path before rushing into action.

You'll solve it.

Egon

 

[aardvark]

Does the filter have a check valve, and is there the possibility it is installed backwards? A low flow condition via the manual pump might not engage the check valve, but cranking the engine creates a high demand, and maybe it then trips the check valve?

 

[slowrev]

One thing I learned working on heavy equipment in the past. For diesel fuel filters I always put them down in some clean diesel fuel or pour it over them to be sure they are saturated before installing them, have seen clean dry ones be very slow to allow fuel to pass thru them. Seemed to work for me.

Ben

 

[MMM]

Some filter heads require a small gasket at the threaded pipe (mine always falls off). Also you can tap on fuel lines with blunt tool to loosen lodged dirt. I flushed my tank a few weeks ago and had same problem due to line blockage afterwards. A few raps with screwdriver handle got it going again. I plan to remove lines and blow them out when I get back from overseas.

 

[KennyV]

Dave...
It sounds like you have air in your injector pumps… If you have a leak in the system between your primer pump and the injector pumps you would be leaking fuel… Since you are not, it’s a safe bet that its solid fuel to the injector pumps.
I’ve never had this problem with any of my Kubota engines. . . But I sure have with cat engines.

The only way I could get them to run, is to start the engine using WD40… It will allow the injector pumps to operate fast enough to push air out your bleeder circuit. Cranking speed is not fast enough sometimes to do it.

I’d start it with a spray into the hose on the clean side from your air filter. You don’t want an oily air filter…
Use compressed air to blow dust away from that area, before you open it, then the running engine will not pull dirt into the intake.
Around 5 to10seconds running on WD40 will have it pumped out.

You can do the same thing using propane but I’ve always figured WD40 is not as ‘dry’, and it’s easy/handy to use. Good luck... over 10 hours is TOOOO long /forums/images/graemlins/crazy.gif, Having that kind of fun.KennyV.

 

[RalphVa]

A couple things happened to me on my 1983 Benz over its lifetime of fuel filter changes, which are normally no sweat.

Once, it wouldn't start. Cause was radial cracks in the flex, rubberish lines from the fuel tank line and from the initial fuel filter. Air was sucking in through the radial cracks.

Another time, my hand pump base came loose. It actually started then but ran rocky. Saw the hand pump base rocking away, kinda independent of the engine. Tightened it up. Fine now.

Your tractor may or may not have any of these possibilities. Just something to look for.

Ralph

 

[Gatorboy]

WooHoo! I got it started tonight.

I removed the fuel filter, and lo and behold there was NO FUEL in it. The problem was the filter came with 2 large O-rings and I put one on the bottom and one the top and screwed the filter on. Well....the top O-Ring actually covered the section where the fuel was to flow into the filter! Doh!

I had kept assumming that because when I loosened the nut and pumped the fuel pump, fuel flowed without any air bubbles, that was full and not the problem. Well, I removed the top O-Ring and reinstalled. Then everything started flowing as it should have -- and 10 minutes later the engine was running.

Thanks for all the suggestions. I'm sure others will have trouble someday, and this thread will hopefully help them out as well. /forums/images/graemlins/grin.gif

 

[Henro]

10 hours to find it...10 minutes to fix it!

That's the way it always seems to work for me too! /forums/images/graemlins/shocked.gif

Man am I glad you got it fixed! Now we'll all be able to sleep tonight... /forums/images/graemlins/grin.gif