CA Carb Advisement
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=42500
Printed Date: 30 Aug 2025 at 12:33am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: CA Carb Advisement
Posted By: Turbo_760
Subject: CA Carb Advisement
Date Posted: 21 Dec 2011 at 10:58pm
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Got the ignition system working on the CA I picked up. Previous owner had timing so far off when I set it I had to move the plug wires around.... Now the tractor will fire right up and will continue to run, but then it seems to be starved of fuel. If I manipulate the choke when this happens I can keep it running, otherwise it will eventually die. I took the carburetor apart (Marvel Schebler) and cleaned it. Put the carb back on using all the same gaskets. (I did this before I fixed the ignition) The float doesn't seem to be sticking as I can open the drain and fuel will pour out. So I think I have a carb issue so what are my options 1) The marvel schebler doesn't really impress me as it has virtually no adjustments. It only has idle air/fuel. I looked on line and there are Zenith replacements which appear to be adjustable, they are a bit pricey but I have not ruled them out. However the serial number on my tractor is 3686 which means it is a 1950 and the zenith says for 52-56 only? What change that would prevent me from using this carbs? 2) Is the marvel a decent carb and I should just get a full rebuild kit for it? 3) Should I look for some other problems like the governor or?? The engine doesn't surge it runs steady and then will start to die Suggestions?
------------- 1951 CA Cub Cadet 149 |
Replies:
Posted By: Jeff Z. NY
Date Posted: 22 Dec 2011 at 4:43am
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I would remove the bowl from the tank and inspect that first.
Sometimes the inlet to the bowl get's plugged with crud slowing the flow of gas. Remove the main nozzle in the carburetor also and clean that good. There are tiny holes on the side of it that get plugged. ------------- I Love Meatballs and Dumplings on Toast with Gravy and Rosemary and ??? {Open For Suggestions} |
Posted By: Jeff Z. NY
Date Posted: 22 Dec 2011 at 4:51am
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Also spray some carb cleaner near all the shaft ends with the engine running and see if engine dies a little, the seals could be bad and the carb is sucking in too much air.
It does sound like a restriction in the carburetor somewhere. ------------- I Love Meatballs and Dumplings on Toast with Gravy and Rosemary and ??? {Open For Suggestions} |
Posted By: Jeff Z. NY
Date Posted: 22 Dec 2011 at 5:01am
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However the serial number on my tractor is 3686 which means it is a 1950 and the zenith says for 52-56 only? What change that would prevent me from using this carbs?
Probably just a linkage thing with them. I have two of the new Zeniths and they are also built for many other application. I had to make some linkange changes for the one's for the B and C. I also had to use 3 gaskets as they say to get the clearance for the throttle plate. They do work good. Tractor runs like brand new. Smooth. ------------- I Love Meatballs and Dumplings on Toast with Gravy and Rosemary and ??? {Open For Suggestions} |
Posted By: Dick L
Date Posted: 22 Dec 2011 at 5:54am
If your carburetor only has one adjustment screw up by the neck it would only be for (IDLE) adjustment. The main fuel jet would be an orifice sized to the engine air flow thru the venturi.
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Posted By: Steve in NJ
Date Posted: 22 Dec 2011 at 6:26am
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Basically, the Marvel carbs perform quite nicely when rebuilt correctly. Be careful of "universal" carburetors. Yes, they fit numerous applications, but not all applications and may overfuel or underfuel certain engines. I believe the TSX-154 or 159 came on the CA which is designed for that particular engine for air/fuel ratio. Stick with what comes on the engine and you won't open up another can of worms. The universal carbs with their erector set bracketry are a PIA sometimes when it comes to throttle/govenor hookups. We offer rebuilding services, parts, rebuild kits, and whatever you may need for your M/S carb. If you need to close the choke to get it to run better, its suckin' air somewhere. Could be through the old re-used bowl gasket, a loose throttle shaft, carb to intake mounting gasket, or manifold gasket. Any of those area's will cause the engine to run rough or die. An easy way to detect where your leak is is with a can of carb cleaner. Spray a little around these area's and see if the engine irons out for a second or so. If you decide to rebuild the carb, make sure the fuel tank is clean and free of trash and debris. Also blow out the fuel line. Installing a gravity feed type fuel filter will help also keep debris out of the carb especially if you rebuild it or have it rebuilt. HTH
mailto:Steve@B&B - Steve@B&B
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Posted By: captaindana
Date Posted: 22 Dec 2011 at 6:36am
| Turbo I hear ya! I have many times had thoughts of "is this piece of 60 some year old #$%^ really worth keeping? Let me tell you if you have some FOD in the carb it will run terrible but I can attest once you get it clean it runs amazing. I installed a replacable clear filter between my fuel shut off valve on the tank and carb many many moons ago. This summer my son said the CA runs like crap so when I got home from jetting I changed the filter and unhooked a few things around the carb and blew some compressed air here and there. It still ran like crap so I kept mowing and when it would falter I pulled on the choke to help. After a couple of outings the spek of dirt disappeared and the little CA ran like new. I don't know how the speck got through into the carb through that filter nor do I know if it was in the carb or tanks outlet but when the spek left all returned to normal. The old stuff works well when clean of foreign objects and don't forget to make sure the cap is venting. Good luck! Dana |
Posted By: GregLawlerMinn
Date Posted: 22 Dec 2011 at 11:59am
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Many of my rehabs came to me with the sediment bowl screen missing. It appears that it was easier to remove the screen than to clean it or replace it. When this happens, the fuel is not filtered and crud can get into ther carb and/or lines. clean or replace the screen. The Marvel carb, when properly cleaned, is a decent carb. Lots of good advice provided to help you locate the problem. I now always roll up a used sediment bowl screen and insert it into the bowl inlet so that 1" is sticking up before screwing it into the tank. Check out your fuel system, clean it as recommended before you invest in a new carb. ------------- What this country needs is more unemployed politicians-and lawyers. Currently have: 1 D14 and a D15S2. With new owners: 2Bs,9CAs,1WD,2 D12s,5D14s,3D15S2s, 2D17SIVs,D17D,1D19D;1 Unstyled WC |
Posted By: DSeries4
Date Posted: 22 Dec 2011 at 5:30pm
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I heard the Marvels were the best ones out there. Once they are set correctly, they don't need to be adjusted again. Once you get the whole fuel system cleaned: tank and strainer (and fresh clean gas), you will have good gas flow to the carb. Then you just need to set it and forget it. Marvels are all I have on my tractors. ------------- '49 G, '54 WD45, '55 CA, '56 WD45D, '57 WD45, '58 D14, '59 D14, '60 D14, '63 D15D, '66 D15II, '66 D21II, '67 D17IV, '67 D17IVD, '67 190XTD, '73 620, '76 185, '77 175, '84 8030, '85 6080 |
Posted By: Gerald J.
Date Posted: 22 Dec 2011 at 6:04pm
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Except for the rectangular die cast aluminum model used on 190, JD 3020, and 4020. Gerald J. |
Posted By: Turbo_760
Date Posted: 22 Dec 2011 at 6:26pm
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So today I pickedup a can of Napa Carb cleaner... I pulled the carb apart and put it in basket and let it soak for 20 minutes. I pulled it out cleaned it off and dried it before I reassembled it.
I also hooked a different fuel tank with a rubber line to the carb. With this setup the engine will run for a short burst and then die. It will then start back up and run for a little bit more. Seems like a sticky float but I can never catch the float prevent fueling from going in. I can pull the plug on the bottom and there is always fuel that will just keep running out..
It backfired a few times through the intake... this make me question my timing
I followed the method posted here.
http://dueyschutter.freeservers.com/photo4.html - http://dueyschutter.freeservers.com/photo4.html
After rereading this it seems that I set it to Fire at FIRE mark on the flywheel and not TDC. I will got try and fix that see if it runs better.
------------- 1951 CA Cub Cadet 149 |
Posted By: Turbo_760
Date Posted: 22 Dec 2011 at 8:36pm
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Open up the carb again, looked like I missed an orfice down by the bottom of the main jet removed. tried to remove the orfice on the top half by the fuel need seat and snapped off the screwdrive slots... should I continue to try to remove it or just leave it. What does this orfice control?
 ------------- 1951 CA Cub Cadet 149 |
Posted By: CTuckerNWIL
Date Posted: 22 Dec 2011 at 9:19pm
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I believe that is the idle jet. Pretty important part of the carb. Ya might have to drill it out?????????
------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: Chalmersbob
Date Posted: 22 Dec 2011 at 10:01pm
| if you flip the top over I think the idle jet screw is there. Remove it and run a very fine wire through the hole in the orfice. It should be ok if it is clean. I had a carb on a tractor that wouldn't idle. I cleaned that orfice and it works perfectly now. When it is back on the tractor, remove the plug in the bottom and let the gas run for several, 3-4, minutes and watch the fuel flow. It won't be fast but it should be steady. Bob |