Farm Equipment - Engine not starting

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Engine not starting

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=37135
Printed Date: 20 Aug 2025 at 12:50pm
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Topic: Engine not starting

Posted By: garyallis
Subject: Engine not starting
Date Posted: 12 Sep 2011 at 1:34pm

1937 WC crank only... got spark and gas and right firing order... but it will not start. Is there a possibility that the magneto is not hot enough? How do you check?

Replies:

Posted By: GlenninPA
Date Posted: 12 Sep 2011 at 1:54pm

Pull a plug out and crank it over. Look for a strong blue spark.

Are you sure you have good gas, and no water in it?

Barring that, maybe you want a friend to give it a whiff of ether while you crank it?

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Good judgment comes from experience. Experience comes from bad judgment.
From listening comes wisdom and from speaking comes repentance.
Wise men learn more from fools than fools from the wise.

Posted By: garyallis
Date Posted: 12 Sep 2011 at 2:14pm

it does have spark but it's more a yellowish red... is there a way to test the spark from the magneto?

Posted By: ALinIL
Date Posted: 12 Sep 2011 at 2:19pm

Gary - DO NOT do the ether and hand crank routine. Does it have good compression? Does the mag have a good impulse and a strong blue spark? Has the tractor been sitting for a long time? If so the gas is probably stale. Drain the system including the Carb. With the throtle cracked, choke the engine and crank. If still no start check a plug to see if wet. If not you might have leaking manifold gaskets. Hey, its an AC, it will run. - AL

Posted By: GlenninPA
Date Posted: 12 Sep 2011 at 5:36pm

yellowish spark generally means the condensor needs replaced in the mag. Cheap fix.

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Good judgment comes from experience. Experience comes from bad judgment.
From listening comes wisdom and from speaking comes repentance.
Wise men learn more from fools than fools from the wise.

Posted By: Coke-in-MN
Date Posted: 12 Sep 2011 at 5:46pm

If your having the cranking problem, after you put fresh gas in it try pull starting it instead of cranking .. Use top gear and if timing and gas are good , well next would be wires and plugs . Make sure plug wires are copper and not graphite wires.

When did it run last ? the other thing if it has set for long time valves could be stuck, take compression check, do a leakdown chack and out compressed air into each plug hole and listen for air , move each cylinder to TDC or bottom of stroke when testing.

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Life lesson: If you’re being chased by a lion, you’re on a horse, to the left of you is a giraffe and on the right is a unicorn, what do you do? You stop drinking and get off the carousel.

Posted By: Chalmersbob
Date Posted: 12 Sep 2011 at 10:19pm

I got out one of my B's last week, had not run in 3 years. Checked gas, still had some in it. Installed new battery, and it started. I drove it 10 feet, and it stopped. I didn't open the gas valve and it started on gas that was in the carb for 3 years. I ran it for 3/4 hour and it started to sputter and dye. Wog some dirt in card. Old gas, stale? I didn't use Sta-bil either. Bob

Posted By: garyallis
Date Posted: 30 Sep 2011 at 7:24am

tried sugestions still no consistint spark cleaned stator replaced coil elimited ground wire

Posted By: Dick L
Date Posted: 30 Sep 2011 at 8:30am

Check the cap. I had to change a cap on one this summer. I had the magneto in the vise checking the spark and it would spark good a coupla revolutions and then would not spark on one or two plug wires. Changed the cap and it worked fine. I could not see anything wrong with the cap with my eyes but a different one worked.

I don't spend much time tinkering with a magneto on the tractor. I have dropites and then can't find the dropped parts in the grass

Posted By: garyallis
Date Posted: 30 Sep 2011 at 8:31am

this is spark at the points points good new condenser

Posted By: garyallis
Date Posted: 30 Sep 2011 at 9:44am

have trouble with consitint spark won't spark every tine ??????

Posted By: Dick L
Date Posted: 30 Sep 2011 at 6:38pm

The spark at the points does not have the hi voltage from the coil. The spark will just be the voltage that the armature spinning in the magnetic field puts out. It will not be the same as what you get between the plug wire and the plug or ground/block. I would guess that the magnets are weak or the bushings are bad. You can somewhat check the magnets with a screwdriver to see how much pull it has on the screwdriver. They should hold the screwdriver bit quite tight. Hard to check the bushings without removing the armature even with weak magnets as they will hold the armature to one side. I am not sure how you are checking for spark but the impulse has to make a loud snap to spin the armature to get a spark at the points. I have seen where the both dogs would not catch the stop pin every time to load the impulse spring.