clogged fuel lines on 4020

[owens73]

I filled a 6 gal plastic fuel tank to put diesel in for my tractor. Didn't know it at the time, but the tank had debris in it. Later, while operating the tractor, it had a sudden loss of power. I changed both fuel filters and it ran at full power for a few seconds then lost power again. I'm guessing the line has debris in it and that the clog is between the filter and the tank. How do I clean out the line? I assume I need to empty the tank and clean it out, as well? Can that only be done by taking off the tank? Thanks.

Steve

 

[Tx Jim]

Yes the fuel tank can be cleaned by removal and cleaning. Temporarily you may get by with blowing compressed air in the line from fuel filter to the tank. Have you ever drained the bottom of the tank to remove H2O? There's a drain cock on the bottom for this.

 

[owens73]

No, I haven't. I didn't know that was necessary or even an option. I've only had the tractor a couple weeks. I will do that, though. Thanks. The internet is surprisingly pretty empty with info regarding the tractor: not very many parts images, websites dedicated to explanations about repair, etc. I just downloaded an operator's manual and that has a lot of helpful info. Thanks, again.

Steve

 

[jenkinsph]

Steve,
Lots of us think the 4020 was the best tractor Deere ever made. Deere's website has all the parts and drawings you should need just sign up to the parts website free to the public and provides a wealth of information. You can also get the shop manuals on CD too. Lots of these tractors were built and are still popular today.

Here's the link, John Deere - Parts Catalog

 

[roush9799]

I'd take the line loose from the filters, and the other end from the tank and blow air back through it. Then, I'd flush the tank out well before putting the line back on. Could be by chance that you plugged the new filter(s) already if there's a lot of debris. What year is the tractor, the earlier ones had the canister filters, and the later ones had the square one. Possible that an injector got plugged, you can take them off and take them to a dealer and they will clean them and test them for you. May even be possible you have air in the system still after changing the filters.

 

[roush9799]

I thought of this too, did you shut the fuel off when you changed the filters? And remember to turn it back on? I've done that before too.

 

[owens73]

Steve, thanks for the link to the JD parts website. Very helpful. roush, its a 64 model so it has the screw-on canisters. I didn't shut off the fuel line when I changed the filters. I didn't properly bleed the lines, I don't think. After I put the new filters on, I pumped the hand primer about 50 times then cranked the tractor. That's when it ran fine for a few seconds and then lost almost all power. I shut off the tractor and pumped the primer another 50 times or so and it wouldn't crank the second time. From what I read in the operator manual, to properly bleed the line, I'd have to loosen the bleed valve. Is that right? Is that the little plastic turnscrew on the bottom of the lower fuel filter?

 

[jenkinsph]

You should have the bleeders top and bottom of the filters to get all the air out. Try that before cracking the injector lines. Tyoically you would bleed the air from the top plastic screw and water from the bottom plastic screw on double stacked filters. Some of the Deere's had the two filters side by side, primary and secondary. My 4020 had a cube shaped filter IIRC.

 

[Tx Jim]

owens73
Sounds as if air is the problem not debris. After opening top bleeder screw on filter and pumping until air-free fuel comes out then loosen supply line at inj pump and pump until air free fuel comes out,then tightened line. If engine still won't crank then inj lines at injectors will need to be loosened to let air out.

CAUTION: never put you fingers around an inj line with diesel fuel spraying out. The fuel can get injected under the skin which is very dangerous.

 

[Tx Jim]

Some of the Deere's had the two filters side by side, primary and secondary.

3020's but not 4020's had side by side fuel filters. Also 2 cyl diesels had side by side fuel filters

 

[jenkinsph]

3020's but not 4020's had side by side fuel filters. Also 2 cyl diesels had side by side fuel filters

Notice I said "some of the Deere's" speaking in general, my 3020 must have had the side by side filters, honestly don't remember that has been a few years. My current smaller 820 has side by side filters with lower glass bowls.

I agree with the problem likely being air in the system as I don't think the trash in the fuel line would cause the almost instant problem after changing the filters but is in line with air entrainment at the injector pump. If the OP didn't know to bleed the air from the top of the filters prior to attempting to start it I think it is a "given".

 

[dminer]

It is usually a good idea to prefill the filters with fuel before installing whenever possible. It makes for a lot less air to remove from the system.

 

[roush9799]

You can't prefill the top one, it is upside down. You have to open the top bleeder and pump and pump and pump and finally you get fuel out of the bleeder. It may take 200 pumps or more to get them full depending how strong the primer pump is. Once you get fuel to there it should start unless you have air pumped in the lines. If so loosen (just have to loosen it a bit) the farthest one from the filter and crank it over a bit. Tighten it and if it starts your good, if not go to the next farthest and on down the line. It will finally hit once you get enough air out.

 

[Tx Jim]

You can't prefill the top one, it is upside down. You have to open the top bleeder and pump and pump and pump and finally you get fuel out of the bleeder. It may take 200 pumps or more to get them full depending how strong the primer pump is.

Unless one cheats like I do and blow short bursts of compressed air in fuel tank neck with a rag stuffed in hole to block escaping air to force fuel into the top filter. My finger doesn't get as tired hold air blower trigger down as pumping lever on the lift pump.

 

[owens73]

I didn't see the rest of the responses before I went back to my farm yesterday to try and get the tractor running again. I opened the bleeder valve on the top filter and pumped the primer until fuel came out of the bleeder valve. The tractor started right up and ran well for a couple seconds, then died. It did that 4 or 5 times. I then left the bleeder screw backed out a bit and started the tractor and it did the same thing. So, I need to bleed the injector lines?

 

[owens73]

I said I pumped the primer and then the tractor started and ran well for a couple seconds then died, and "it did that 4 or 5 times." I only pumped the primer one time, before starting it the first time. The other 4 or 5 times, I waited a few seconds after the tractor died, then cranked the engine.

 

[Tx Jim]

Before loosening inj lines I'd suggest loosening supply line at inj pump and pumping lever on lift pump until air free fuel squirts out and then tighten nut on line.

 

[roush9799]

Before loosening inj lines I'd suggest loosening supply line at inj pump and pumping lever on lift pump until air free fuel squirts out and then tighten nut on line.

Worth a shot, but since it's dying, the air is probably in the whole system between the injectors and filters. You may luck out and get enough air out that it will start and keep running till all the air is purged out.

 

[jenkinsph]

I agree with Tx Jim do the easy stuff first, and the injector pump inlet is a good bet. I should also mention that Jim is a very helpful retired Deere shop foreman and tractor mechanic with lots of Twenty series experience.

 

[Tx Jim]

There's also another possibility that the fuel return line fitting is plugged with debris. A plugged return line will allow engine to start/die,start/die