Cleaning fuel tank?

[Jason280]

I recently ran into a low-power issue on a Ford 3930, assuming it was the fuel filter. I changed the filter, and on attempting to prime to the top of the filter housing, noticed it wasn't getting fuel. I pulled the fuel line from the cutoff, at the bottom of the tank, and noticed fuel was only trickling out of the cutoff valve (when fully opened). I cleaned/blew it out with compressed air, and was able to get full fuel flow out of the valve and to the filter and injector pump. Unfortunately, this only lasted about a week, and its showing the same symptoms again.

I'm assuming this is trash/debris at the bottom of the tank, which is settling and clogging up the cutoff valve. Do these tanks have some sort of lower filter in the bottom of the tank? I don't see any of the tell-tale growth at the fuel cap or fuel neck, so I am not sure exactly what is causing the clogging. This is one of the poly/plastic tanks, and looks like a PITA to completely remove....what would be the best way to flush out the tank without removing?

 

[Harry in Ky]

Most all of the Ford tractors of that size from '65 on used a similar shut off tap. Yes it has (or at least had) a screen in the fitting up inside the tank. Your problem is not at all uncommon.

I won't claim to have the "best way" to solve it, but what I do is first siphon as much fuel as possible into CLEAN open buckets. Then unscrew the fitting and drain what's left, catching what I can into a drain pan or bucket using a makeshift cardboard funnel to direct the fuel as much as possible. Then using some of the best looking fuel from the first step, rinse the tank a few times with a quart or so until what comes out looks clean. Clean the screen and put it all back together. I have done that many times on many tractors and had good success.

 

[Jason280]

I drained the tank, and completely removed the cutoff valve...I'll post a few pics later, but the small in tank filter was completely covered in fungus...it was actually crazy to see. I took some time to flush the tank as well as possible, and was able to get it pretty clean....flow out of the cutoff is plenty for the filters.

Problem is, now I can't seem to get the system correctly bled. I bled to the filter housing, injector pump, and each individual injector, but its still running on (what feels like) half throttle. I again checked the cutoff, and fuel flow is more than adequate. I bled everything again, and still having the same problem.

I can't imagine I am bleeding incorrectly, I am getting pulsing fuel out of the injector lines at the injectors...any suggestions?

 

[stevem5215]

Pump could have been damaged by the junk in the tank too. Injector pumps do go bad.

 

[Jason280]

I see no evidence of any of the "junk" getting past the sediment bowl, and none was in the filter or filter housing.

 

[Roadworthy]

I've had the same problem. Instead of assuming I was bleeding correctly I actually consulted the manual and found one step I was doing wrong. Problem fixed.

 

[Raul-02]

.what would be the best way to flush out the tank without removing?

you could use an aqueous solution with something like water soluble cutting fluid in it to prevent rust (or antifreeze). then use a wet/dry shop vac. you'd have to be sure to vacuum it all, and then a couple rinses with with methanol before drying it out.
But the tank is removable.

 

[Jason280]

I've had the same problem. Instead of assuming I was bleeding correctly I actually consulted the manual and found one step I was doing wrong. Problem fixed.

Which step were you missing/doing wrong?