Farm Equipment - D21 fuel issues

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D21 fuel issues

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=206287
Printed Date: 15 Apr 2025 at 6:49pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: D21 fuel issues

Posted By: acplowboy45
Subject: D21 fuel issues
Date Posted: 13 Apr 2025 at 1:10am

Fuel issues I have been dealing with for the past 2 weeks off and on. It will start right up even after sitting a couple of days. Run it drive it down the road and by the time I get back to barn it dies runs the fuel filter dry. Now bowl in back of tank is clean. The break in the line I can take it off and it will pee a stream of fuel every time. I have blew out the return line and there clean. I can pour fuel into the top of filter canister prime it up a little bit and will start right back up. What am I missing.

Replies:

Posted By: DrAllis
Date Posted: 13 Apr 2025 at 3:36am

Blow backwards into the tank. The outlet to the tank is plugged or hand primer has a blockage.

Posted By: Straanger
Date Posted: 13 Apr 2025 at 10:59am

Leave the fuel cap loose and try it again

Posted By: acplowboy45
Date Posted: 13 Apr 2025 at 12:17pm

I have left fuel cap loose and blew both ways into fuel tank. It's still wants to drain fuel filter. I'm thinking I need to replace plunger would that cause problems?

Posted By: 55allis
Date Posted: 13 Apr 2025 at 2:50pm

Drain the tank and look down in it, might be something that sucks down and it releases after it’s shut down…

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1955 AC WD45 diesel with D262 repower, 1949 AC WD45

Posted By: den/southern illinoi
Date Posted: 13 Apr 2025 at 4:37pm

May not be the problem but we had a used skid steer that we were testing and after running a while it would shut down. Upon inspection there was a stick (someone's fuel gauge) in the tank that would float to the fuel intake and shut off the fuel flow. We ended up opting for a new skid steer.

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Own 4 wheel 20, 2-5015, 5020 and associated equipment and 2 electric forklifts.

Posted By: Codger
Date Posted: 13 Apr 2025 at 4:53pm

I have seen that happen with a polypropylene cloth shop towel dropped into the tank more than once.

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That's All Folks!

Posted By: wjohn
Date Posted: 13 Apr 2025 at 4:57pm

Not at all a diesel, but I had a very similar fuel issue on my Super M. There were multiple dead moths semi-suspened in the fuel tank that would eventually get drawn to the outlet and starve the tractor. If I let it sit for 10 minutes the moth carcasses would eventually drift/float away from the outlet and it would fill the carb again. Blowing air through the fuel line obviously didn't get rid of them for long and they would just keep getting drawn into the outlet until I figured out what was going on and pulled them out.

I'm not familiar with D21s at all but I would do my best to shine a light, bore scope, whatever you can do down the tank to make 100% sure there isn't a piece of junk in there before I tore anything down. Then work forward in the fuel system from there. Sounds like you have ruled several things out already.

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1939 B, 1940 B, 1941 WC, 1951 WD, 1952 CA, 1956 WD-45

Posted By: 8070nc
Date Posted: 13 Apr 2025 at 5:28pm

Neighbor had a 1566. It did the same thing. Turned out there was a golf ball in the tank. It would suck down and cover the outlet. When it cut cut off it would pop back away. Bleed it and it would run a while longer. Neither here nor there

Just a story

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1984 80780
1957 D14
DES 300 with 25000 engine
616 tractor

Posted By: AC720Man
Date Posted: 13 Apr 2025 at 8:17pm

Aluminum foil from a bottle of fuel additive stopped our 6060 when it got down to 1/8th-1/4 of a tank of fuel. Put more fuel in it and it ran fine. Finally pulled the tank later that summer and flushed it out. Quite shocked that the dime size piece of foil caused such a problem. Sounds like you may have something in there for sure as others have said. Just letting you know what happened to us.

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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD

Posted By: acplowboy45
Date Posted: 13 Apr 2025 at 10:05pm

Anyone have a decent used fuel tank for a D21 for sale. I have pulled this tank off flushed it. It did have some rust build up from sitting. I guess I'm going to have to pull tank back off and start over...STILL ANY USED D21 TANKS..PLEASE LET ME KNOW. Thanks for your help guys.

Posted By: DrAllis
Date Posted: 13 Apr 2025 at 10:46pm

You've had the tank off once already ?? Did you use a power washer and aim it in thru the fill hole?? and then aim it in thru each sediment bowl hole (sediment bowls removed) and drain/flush?? doing this more than once ?? I've only seen one tank bad enough that this method wouldn't work. The tractor (220) had been sitting 25 or so years. I feel it was going to require tank removal, cut open each end of the tank and clean with a power washer from each end or maybe sand blast too. It also may have required cutting the tank open underneath where the seat suspension track is and doing the same thing. Any good semi truck repair shop works on truck fuel tanks can do this. Each location is out of sight when the piece removed is welded back in place. The paint will match when you get done. I sold this tractor with the new owner knowing this. Don't know what he did for sure. EDIT: You should be able to look in thru the fill neck and get a good idea what it's like on that end of the tank. I would cut open the opposite (right) end first and see if that might be enough to get her cleaned out before cutting open both ends and the seat track area.

Posted By: JimWenigOH
Date Posted: 15 Apr 2025 at 11:23am

I had a similar issue with my 220. After running down the road for 8-10 mile it would act like it was running out of fuel (which it was) and eventually die. I'd pull over, try to pump the primer pump which was very stiff. Seems the injector pump was pulling a vacuum on the primer pump due to an internal check valve in the primer pump which was not working properly. Tried the loose fuel cap deal which didn't help. Installed a new primer pump and it's been working properly for the past 13 years.