1938 B starting issues
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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=36687
Printed Date: 02 Sep 2025 at 5:30pm
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Topic: 1938 B starting issues
Posted By: Jazzy32
Subject: 1938 B starting issues
Date Posted: 04 Sep 2011 at 10:16am
| Hey folks I've run into a bit of an issue. I use my 38 B with woods mower for finish mowing at my canoe rental business. I mow about thirteen acres at a time and the tractor gets used for very little else. So yesterday I have my helper jump the tractor and when he does he neglected to change the jump box setting to six volt from twelve. Well as I'm sure some of you know the twelve volt jump was too much for the six volt battery and the battery gave up and the top exploded. So I installed a new battery today and now the tractor won't even attempt to start. I've got power everywhere and the fuse isn't blown. It's just not attempting to start. Could it be a problem with the pull switch. Would the starter turn no matter what even if the mag switch isn't turning on. Or will I need to replace that switch first. In the past with other vehicles I've bypassed switches and the like by using a screw stick to jump the terminals on the starter motor. But I don't see a way to cross the terminals on my B. Ideas???Please help!!! |
Replies:
Posted By: Alberta Phil
Date Posted: 04 Sep 2011 at 10:31am
| Mag switch should not be affected as all it does is ground out the primary circuit. Your problem is probably in burned contacts in the switch on the starter. If you remove the two screws from the switch on the starter, you should be able to check the contacts and try to bridge them with a heavy bar or screwdriver and see if the starter works. |
Posted By: CTuckerNWIL
Date Posted: 04 Sep 2011 at 10:38am
|
First off the mag switch only grounds the mag to kill your spark and has nothing to do with the starter. If the starter does nothing now, I would double check connections to the battery first. They must be clean and making good contact to work properly. I have jumped 6 volt tractors with 12 volts before and never had a problem. Did he jump it backwards with negative to ground maybe? If the starter turned over before the battery blew up, I would check to make sure the starter isn't jammed in the flywheel ring gear by breaking the starter set screw loose and pulling the starter out a little first disconnect the ground from the battery . To inspect the "pull" switch on the starter, after the ground is disconnected, remove the battery cable and pull the cover. There is a little bronze nub sticking out of the starter that the mechanical switch contacts to energize the starter. These can be filed a little if contact is poor. Do not loose the cardboard lining inside the switch or you could have trouble with shorting out later. In order to "jump" the starter switch, you would need to remove it from the starter and connect battery power directly to the nub sticking out of the starter. Hope this helps. Let us know what if you figure it out. ------------- 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: Jazzy32
Date Posted: 04 Sep 2011 at 11:09am
|
Thanks for the advice. My guy had the jump box hooked up right pos to pos neg to neg. It may be that it was an older battery and couldn't handle the voltage jump. I've seen it happen only a few times in old six volt VW's but they were old batteries to begin with. It went off like a grenade and scared the dirt out of my young guy. He jumped right out of his skin.
I will pull the cover on the starter and try jumping the terminals. I will post the results as I come by them. If jumping the switch doesn't get a spin out of the starter I'll move move down the list of possible solutions. Any more ideas keep em coming. Thanks. |
Posted By: Dick L
Date Posted: 04 Sep 2011 at 11:18am
| I only use my jump and carry 12 volt to start my 6 volt tractors. I have never blown a battery. I never hook to the battery though, I hook directly to the starter and frame/engine bolts. |
Posted By: Chalmersbob
Date Posted: 04 Sep 2011 at 9:03pm
|
It doesn't matter where you make your connection, it is still being connected to the battery. We always used a 12 volt battery to jump start a 6 volt car or truck. We also used a 12volt high output charger to jump 6 volt batteries, I am using my 12 jumper box on my D14 (6 volt) right now, starting it after a fresh rebuild. Bob |
Posted By: CTuckerNWIL
Date Posted: 04 Sep 2011 at 9:10pm
Bob, I beg to differ, it absolutely does matter if your battery is giving off hydrogen gas and you hook the cables up next to the gas. It also matters if you make the last connection near the weak gaseous battery. Always make the last connection to the ground point away from the battery. ------------- 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 |
Chalmersbob wrote:Posted By: Chalmersbob
Date Posted: 04 Sep 2011 at 9:19pm
|
Point well taken!!
Also make the connections before you plug in the charger or turn on the jump pak. Bob
|
Posted By: Dick L
Date Posted: 05 Sep 2011 at 7:34am
| Often when I hit the starter I see sparks or hear it fry at the jump clamps as it gets the full load of the draw to spin the starter. |