Farm Equipment - Allis B

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Allis B

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=212178
Printed Date: 17 Sep 2026 at 4:08pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: Allis B

Posted By: john2189
Subject: Allis B
Date Posted: 07 Sep 2026 at 5:09pm

Lately when mowing grass, my B cold start needs no choke at all, ever.
After about five minutes or so it starts running rough. If you pull choke a bit, it evens out and runs great. Push the choke in, and it starts running rough again.
Why would it not get enough gas after warm up?

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'41 Allis B
'49 Farmall Cub

Replies:

Posted By: steve(ill)
Date Posted: 07 Sep 2026 at 5:30pm

your main jet in the carb is partly plugged... so it takes no choke ( restrict the air) to start... As it warms up, you dont have enough fuel to mix with the air available.

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Like them all, but love the "B"s.

Posted By: john2189
Date Posted: 07 Sep 2026 at 10:18pm

Thanks, I’ll pull the jet and check it. In fact I was thinking about getting a kit and rebuilding the carburetor.

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'41 Allis B
'49 Farmall Cub