Farm Equipment - B Engine Surging

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B Engine Surging

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=20642
Printed Date: 10 Feb 2025 at 7:26pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: B Engine Surging

Posted By: morton(pa)
Subject: B Engine Surging
Date Posted: 10 Nov 2010 at 8:05pm

Alright, I'll admit, I'm baffled.

Got the '52 B up and running for the first time in a few months. Put the sickle bar mower on, and noticed something way out of the norm. At certain points, for no reason (for instance, sitting idle at half throttle) the engine would start to surge. My question is, what could be causing this? I watched it happen and I have no idea what could be causing it. Maybe a bad spring somewhere? I don't think the magneto would cause something like this, would it? I'm assuming it has to be something with the governor, but I've never had, seen, or heard of anything like this happen before. Anybody else have this happen or know how to fix it?

Replies:

Posted By: Jerry (Ohio)
Date Posted: 10 Nov 2010 at 8:17pm

You need a surge spring on the rod going to the carb. You can get one at your Agco Dealer

Posted By: morton(pa)
Date Posted: 10 Nov 2010 at 8:47pm

I'm pretty sure it's there. I checked everything I could think of for normalcy since I had the mag off. Maybe I'm missing something else?

Posted By: Rog(NCWI)
Date Posted: 10 Nov 2010 at 8:56pm

This is the spring that is attached to one of the manifold studs and is hooked into the small hole in the rod that goes to the carb. Some times these springs get weak from the heat by the manifold end and lose their tension. To me I think they are kind of pricey but what is't these days.

Posted By: RyanTN
Date Posted: 10 Nov 2010 at 9:04pm

You might also want to check to see how tight the throttle shaft on your carburetor is. If there a lot of slop between the bushing and the shaft, that could be one of several reasons for your surging.

Posted By: morton(pa)
Date Posted: 10 Nov 2010 at 9:21pm

Rog yes I know which one it is. Ryan, I'll check that out.

Posted By: Thad in AR.
Date Posted: 11 Nov 2010 at 4:37am

Choke it just a little and see if it clears up. If it clears up then it's old gas or carb needs cleaned. After mine set awhile I put fresh gas with pour in the tank carb/injector cleaner. HTH Thad

Posted By: Dick L
Date Posted: 11 Nov 2010 at 6:26am

You will find your problem in the connection between the cross over governor arm and the linkage to the carburetor. At idle you need about 1/16 inch pressure on the butterfly stop screw. The cross over has to be bent to make the adjustment. You can have more than 1/16 of an inch pressure holding the butterfly closed but it will cause a lower fast RPM.

A governor is a RPM limiter and when you do not have this pressure from the weights holding the fuel back with the butterfly more fuel gets into the engine which speeds up the engine and then the governor says Oh NO and starts to close the butterfly but then over closes the butterfly because of a lack of pressure form the spinning weights which in turn lets the governor open the butterfly and it starts all over again. That is called surging.

If you are right on the edge of this setting the surge spring will help but if you are off much a surge spring can not over come the problem.

Posted By: Brian Jasper co. Ia
Date Posted: 11 Nov 2010 at 11:34am

I had a similar surge once on my CA. It was getting debris in the main jet. It had a new sediment bowl on it. Turned out to be coming from inside of the metal fuel line. Fabbed up a new line and haven't had carb problems since.

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"Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford

Posted By: Good
Date Posted: 11 Nov 2010 at 1:11pm

I've had them surge from what DickL said but it's usually from a new engine setup, my dad has gotten real good at bending to the right distance.I would say your B would be fuel or carb since nothing has changed on linkage. Is there anyway one govenor weight could be froze?

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B212,716,two 314H's,WC,WD,D19,190XT