1937 WC Carburetor float adjustment
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=196001
Printed Date: 12 Nov 2025 at 11:07am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: 1937 WC Carburetor float adjustment
Posted By: H_36754
Subject: 1937 WC Carburetor float adjustment
Date Posted: 04 Jul 2023 at 11:47am
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I'm working to restore a '37 WC that belonged to my grandfather before his passing in 2011. It's been sitting in the shop for the better part of 12 years and I've been working since the beginning of this summer to restore it back to running condition. The only thing holding me back is the carburetor. It is original to the tractor, and it is a Zenith 7078. I have rebuilt it with a kit, but I can't get the float set right. The directions that came with the kit are too vague. Can anyone send pictures of how to set it to the right level?
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Replies:
Posted By: Eric B
Date Posted: 04 Jul 2023 at 12:09pm
Unless the new needle is a different length than the original it shouldn't need any adjusting. I have no technical info for you but as a rule of thumb, generally, if you hold up the carb and look at the floats they should be parallel with the 'lid' of the carb as the needle closes. I'm sure more expert advice will come with time in this thread.
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Currently- WD,WC,3WF's,2 D14's B. Previously- I 600,TL745,200,FL9,FR12,H3,816 LBH. Earth has no sorrow that Heaven cannot heal!
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Posted By: H_36754
Date Posted: 04 Jul 2023 at 4:05pm
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It will run, though, albeit roughly and then it stops after about 10 seconds. My theory is that it's just set too low and the float shuts off the needle before more gas can get there from the tank.
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Posted By: Eric B
Date Posted: 04 Jul 2023 at 9:15pm
Have you tried to see what kind of fuel flow you have by removing the plug on the bottom of the carb? It is also possible that there is restriction associated with the fuel shut-off on the tank. I had that on my WD, mind you, it ran much longer that 10 seconds but once cleared it has been perfect.
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Currently- WD,WC,3WF's,2 D14's B. Previously- I 600,TL745,200,FL9,FR12,H3,816 LBH. Earth has no sorrow that Heaven cannot heal!
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Posted By: SteveM C/IL
Date Posted: 05 Jul 2023 at 8:52am
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Basically any carb float should be parallel with the body gasket. Hold part with float upside down letting needle rest in seat....should be in same plane.
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Posted By: Steve in NJ
Date Posted: 05 Jul 2023 at 10:41am
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Your problem may not be the float at all, but may be the new needle valve is hanging up in the seat bore due to a burr or nick. Quite a common problem when manufacturing small brass parts like that. Whenever I rebuild a Carburetor for a customer, I always take a piece of super fine steel wool and polish the needle barrel to make sure it slides in and out of the seat bore correctly. Being the 7078 Zenith has one large Pontoon float, make sure there isn't any fuel in it. Quite a common problem for that particular float assy. Another issue that causes a problem with that particular large float is ice. Let's face it, these Carbs are older than some of the forum members here, and over the years when these Tractors sit outside and get water in them, or there is water in the fuel, ice will form in the Winter months, expand and crunch in those large pontoon floats causing damage to them which in turn causes and operation problem. I've done enough of those dual fuel Carbs to know that. Make sure there isn't any large dents in them. As SteveM mentioned, just make sure the float is level with the machined part of the lid. HTH Steve@B&B
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39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife
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