Farm Equipment - Allis Chalmers B Mysteriously Quits

Print Page | Close Window

Allis Chalmers B Mysteriously Quits

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=25497
Printed Date: 25 Feb 2025 at 5:51am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: Allis Chalmers B Mysteriously Quits

Posted By: JR Maley
Subject: Allis Chalmers B Mysteriously Quits
Date Posted: 09 Feb 2011 at 1:25pm

My B will suddenly quit even without load. I rebuilt the carb and replaced the condenser in the Fairbank Morse Magneto. It has new properly gapped plugs and new gasoline in it. I have a new sediment bowl which I plan on installing real soon and cleaning the fuel line, and I also plan on going back into the magneto and checking/adjusting the point gap.

Like I said, the tractor will be running perfectly, with no lack of power or anything, no miss, etc, but then it will suddenly quit. Does anybody else have any other suggestions? It seemed to me to most likely be a condenser, but the new one didn't fix it. It seems to happen more frequently after the tractor has been running at a higher RPM for a few minutes.

I have heard that many times new condensers are bad from the start. The new condenser also seemed real small compared to the old one (new =3/4" long & old was 1.5" long). Does anybody know the best condenser money can buy for these magnetos? The one I bought was a NAPA FM200 as suggested by the AGCO dealership.

Replies:

Posted By: Gary in da UP
Date Posted: 09 Feb 2011 at 1:34pm

Make sure your gas cap is venting properly

Posted By: RyanTN
Date Posted: 09 Feb 2011 at 1:34pm

I would certainly check the things you have mentioned first, but do you have a remote "kill switch" wired to the magneto? If so, maybe there is a bare spot in the wire that is shorting out and grounding it out. I know it is kind of simple and obvious, but I thought it was worth mentioning.

Posted By: Bill Long
Date Posted: 09 Feb 2011 at 1:52pm

As to the condonser check with Steve B&B he is our resident electrical expert.

The above items are very good answers. One thing I would suggest is to consider the coil. When a tractor stops a lot of time that is it even when we sold them new..

Can't have my favorate not running right.

Good Luck!

Bill Long

Posted By: CTuckerNWIL
Date Posted: 09 Feb 2011 at 2:02pm

Check your spark immediately after it dies. If you have no spark, you may have a bad coil in the mag. Check gas flow by removing the plug from the bottom of the carb. I had the same problem with my CA after a renter"borrowed" it. It took me weeks to figure it out. He had used a Clorox bottle to add gas to the tractor and the cardboard gasket from the cap was half floating in the tank. It would get over the outlet hole and the tractor would die like you turned the switch off. This might happen 2 minutes or 20 minutes after starting and was never consistent.

-------------
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: jjrosty
Date Posted: 09 Feb 2011 at 2:05pm

That sounds like a fuel flow problem. theres enough fuel for slow running & not enough for high RPM. after setting a few minutes the carb bowl fills & runs perfect... for a few minutes

Posted By: allis restorer
Date Posted: 09 Feb 2011 at 3:55pm

check your wires at the kill switch and make sure they are making conection, i had the same problem CA and it ended up that the key switch was bad, it would start and run fine and then just like that it would shut off. i put a new key switch on and its been fine ever since.

Posted By: Allen Dilg
Date Posted: 09 Feb 2011 at 7:11pm

Crud in inlet to sediment bowl

Posted By: Rick of HopeIN
Date Posted: 09 Feb 2011 at 8:39pm

My experience was a magneto that was OK til it got hot, like under sustained load. OK when engine was running cool.
Have had a filter after the sediment bowl on B and it would only run a short time until the filter restriction caused float bowl level to drop. If you suspect fuel line/ filter issues you could run it out of a temporary fuel tank like from an old mower and see if it helps.

-------------
1951 B, 1937 WC, 1957 D14, -- Thanks and God Bless