Allis Chalmers "B" - HELP!
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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=136421
Printed Date: 08 Nov 2025 at 5:09am
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Topic: Allis Chalmers "B" - HELP!
Posted By: dwaynehubbard
Subject: Allis Chalmers "B" - HELP!
Date Posted: 20 Mar 2017 at 4:51pm
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I have a 1947 Allis Chalmers "B" that has sit in the barn for about 4 years. I started 'fixing it up' a few months ago mechanically (cosmetically it is brilliant) and have came to a halt over this infernal matter. I replaced the points, plugs, rotary button, coil, sediment bowl gasket, changed the motor oil and filter, changed the breather oil and thoroughly cleaned the associated breather filter screen. I flushed the gas tank and put clean non-ethanol gasoline in it, so everything is running clear. I took off the carburetor and had it totally rebuilt and replaced it. My issue is that it will immediately start up, however it only runs for about 5 to 10 seconds and then it shuts off. Have have adjusted the carburetor (from a trickle to a full flow) and no effect is noticed one way or the other. The tractor still starts and runs for 5 to 10 seconds and promptly shuts off. Any advice or assistance anyone could give me would be greatly appreciated. Regards, Dwayne Hubbard (770) 683-2900 |
Replies:
Posted By: dt1050
Date Posted: 20 Mar 2017 at 4:57pm
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is it leaking at the manifold. was it running before you started replacing parts?
------------- Just cause it's orange don't make it a tractor, there's only one..Allis Chalmers |
Posted By: dwaynehubbard
Date Posted: 20 Mar 2017 at 5:14pm
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It was running several years ago. It was my fathers tractor and he passed away in 2014. The tractor hasn't really been run since about 2012. It may be around the manifold that is leaking. I had not considered that. The carburetor was rebuilt because I thought it was that which was leaking. However, since the rebuilt one was put on it still streams gasoline somewhat if the flow is strong and steadily set. |
Posted By: Larry in NC
Date Posted: 20 Mar 2017 at 5:16pm
| It is most likely trash in the bottom jet on the carburetor. You almost also always have to disassemble these carburetors and soak them in cleaner to get everything cleaned out. |
Posted By: dwaynehubbard
Date Posted: 20 Mar 2017 at 5:20pm
| The carburetor was taken off and professionally rebuilt. |
Posted By: dawntreader74
Date Posted: 20 Mar 2017 at 5:57pm
| could have a bad coil' check see if it's getting hot' |
Posted By: Dick L
Date Posted: 20 Mar 2017 at 6:31pm
Lets start with the leaking carburetor. Is it leaking out the bottom when setting with the gas turned on at the tank?
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dwaynehubbard wrote:Posted By: Dek Thorne
Date Posted: 20 Mar 2017 at 6:48pm
| Sounds fuel related to me. I would look into the carb. Can u choke it with your hand and get it to run longer |
Posted By: Gerald J.
Date Posted: 20 Mar 2017 at 7:43pm
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These vintage tractors with manual choke and updraft carburetor always require full choke for initial starting and then the choke generally needs to be opened within seconds of its initial firing or it will be flooded and will die. You can tell that by pulling a plug and finding it awash in gasoline. Otherwise you need to determine if its running out of fuel or losing ignition. Either can kill it in a few seconds. A series timing light could show spark. A plugged screen on the fuel inlet adapter to the carburetor or varnish in the fuel line and/or the sediment filter can limit fuel flow. Usually an overheating coil runs more than ten minutes before failing, or a condenser can last that long. Most often a condenser doesn't recover from overheating but a coil often does. Check for spark by taking a plug wire off a plug and hold the bare end of the wire about 3/8" inch from the block and crank the engine. There should be a blue spark that long in air if the ignition is good. Or that could be the wire from the coil to the distributor providing its battery ignition. Gerald J. |
Posted By: Hubert (Ga)engine7
Date Posted: 20 Mar 2017 at 8:01pm
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Sounds like a fuel flow problem, either too little or too much. Even though the carb was professionally rebuilt it could still have a piece of trash floating in the bowl and causing problems. ------------- Just an old country boy saved by the grace of God. |
Posted By: ac fleet
Date Posted: 20 Mar 2017 at 8:15pm
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"Professionally " rebuilt don't mean anything!!!----IF you put on a NEW never used carb, things could be different!----And a side note,---- WERE in H--- do you get NON-ETHANOL gas from????? ,----around here there is no such thing!!!! LOL!!!! Also you might take the needle and seat out and check for free movement, AND make sure the float is set to proper specs.----don't trust "pro.",---check for yourself!!! LOL!!!! thanks; ac fleet |
Posted By: TMiller/NC
Date Posted: 20 Mar 2017 at 8:21pm
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Several places near by that offer ethanol free gas, used in lawnmowers. It cost a little more than the 10% stuff. |
Posted By: TMiller/NC
Date Posted: 20 Mar 2017 at 8:25pm
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From experience be sure the venturi in carburetor is not installed upside down. |
Posted By: Dick L
Date Posted: 21 Mar 2017 at 6:01am
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If the carburetor is leaking it has (DIRT) in it. It is either from the rebuilder or from the gas tank when the gas was hooked back up. Unless the carburetor has been switched it is a (non adjustable) jet carburetor. Dirt getting into the bowel will settle thru the little hole just before the power jet. This is the no adjustable carburetor you should have.  Power jet location  If the idle stop screw is set to fast the above could cause it to not have enough fuel thru the idle circuit. It the rebuilder used a gasket that fit except for a different carburetor and the air hole was not in the gasket. Until you have clean gas going into the carburetor from the tank and the carburetor clean your going to have problems.
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Posted By: Gary Burnett
Date Posted: 21 Mar 2017 at 7:18am
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Rebuilding a carb and not putting in a inline filter is a waste of money on an old tractor as the carb will just fill up with whatever stopped the carb up in the first place.And yes gas will pass thru an inline filter with gravity flow as I have them on every gas tractor I own and have 2 on the tractors with fuel pumps like the D19. |
Posted By: WD45Diesel57
Date Posted: 21 Mar 2017 at 7:27am
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i had my carb professionally rebuilt for my CA couple years ago when I got it put it on wouldn't start so I fooled aroung replacing ignition parts still nothing so I pulled the carb apart, checked the little hole in the bottom where the gas leaves the bowl to the jet and there was a little stone jammed in there and was over looked by the rebuilder! So just because it was professionally done doesn't mean there wasn't something over looked! We are only human it happens! ------------- 1-B's, 2-C, 2-CA's,2-WF, 1-WC,1-G, 3-WD's, 2-WD45, 1-RC, 1-D17 Diesel, 1-D14, 2-D15,1-D17 row crop,1-D19 gas and All Crop 40,60,66,72,90 and 100 |
Posted By: Bill Long
Date Posted: 21 Mar 2017 at 11:24am
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When I was very young I remember my father dissembling the B Carb on a sheet of newspaper so he could well see the parts. He used a very fine wire at the bottom of the carb to clean the bottom jets. Seemed - as mentioned above - a very normal problem: even in the 40's. Also, Check the gas tank for junk. When units sit for a while it takes several good cleanings to empty them of all junk. I remember a CA we got new and while it was on the railroad flat car some wise soul had put sand in the gas tank. We did not know it till we got to the field on a knock down drag out demonstration. Was doing fine when the CA stopped cold. We had to clean the tank and get back in the game. Got the sale. The customer called later to tell us he had to re clean the tank several times before it ran clean. Can't have my favorite and YOUR FATHER'S TRACTOR not running well. Let us know how it goes. Good Luck! Bill Long ps: you have outstanding advice from from excellent mechanics. Listen closely
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