Allis B no spark
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=207730
Printed Date: 11 Aug 2025 at 8:05pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Allis B no spark
Posted By: cjallis
Subject: Allis B no spark
Date Posted: 08 Aug 2025 at 7:45pm
| Got an issue with spark. Tractor has been sitting inside for 10 years. Rebuilt head, lots of new parts. Magneto did throw spark last time I ran it several years ago. I did clean the points. They were dirty. Any help to troubleshoot the issue would be great. |
Replies:
Posted By: steve(ill)
Date Posted: 08 Aug 2025 at 7:52pm
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there may be a corrosion on the point that dont WIPE OFF.... you might want to use a very fine sand paper or point file to get more AGRESSIVE.... Once you guarantee the point is OK... the condenser next to it is suspect, then the COIL. ------------- Like them all, but love the "B"s. |
Posted By: WF owner
Date Posted: 09 Aug 2025 at 7:54am
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You said that you cleaned the points. Are you sure you got the gears timed correctly when you reassembled it? http://dueyschutter.freeservers.com/photo6.html" rel="nofollow - Allis Chalmers Page 4
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Posted By: cjallis
Date Posted: 09 Aug 2025 at 6:12pm
| It actually wasn't timed correctly but now it is. Points I cleaned with a brush.still nothing. Is there anyway to test with a meter at the coil? |
Posted By: steve(ill)
Date Posted: 09 Aug 2025 at 6:34pm
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coils for mags are hard to test.. If it is the old BLACK TAR COIL, it might be suspect...If the coil is plastic coated and red or similar, i would clean the point more agressive ( i dont know how a brush could do it... i would use sand paper or a file) .... and change the condenser.... and make sure the point is not grounded, condenser not grounded, ground strap on the outside of mag insulated.
you can clamp the mag in a bench vise and put a couple wires and spark plugs on and ground them together... turn the mag IMPULSE with a pair of pliers and look for the spark... you can feel the spring WIND UP, then SNAP.. ?? ------------- Like them all, but love the "B"s. |
Posted By: Les Kerf
Date Posted: 09 Aug 2025 at 7:25pm
The secondary windings (high-tension side) of the coil will read somewhere between 5,000-10,000 ohms; if they read open (infinity) the coil is bad. The primary side is more difficult, it will be about 0.5 ohms (that's 1/2 of an ohm). This requires a pretty good ohmmeter, and is not definitive even if it looks good.
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cjallis wrote:Posted By: nella(Pa)
Date Posted: 10 Aug 2025 at 7:47am
| I had a problem with my B mag and sent it to Steve @B&B custom circuits 937632559six. It work well after he fixed it. |
Posted By: ac fleet
Date Posted: 10 Aug 2025 at 8:12am
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had to put a battery dist on my B --- problem solved!! Mags are junk from the word go!! ------------- http://machinebuildersnetwork.com/ |