Farmall A missing on 1 4

chad from michigan · Jul 8, 2011

Went to cut grass at my dads today and the tractor is running crappy. missing really bad changed all plugs and runs the same. Grounded out the plugs to find out 1 & 4 are not firing.
Changed the plug wires and still same problem.
I tried adjusting the points and they were real close to .013" its a mag. could I have problems with the dist cap? or bad points and condensor? what should I be looking at? any help would be great.
Thanks

Tyler Jackson · Jul 8, 2011

Bad plugs?

Tyler Jackson · Jul 8, 2011

Oops missed the changed plugs sentence. Could be points. Make sure all the points dist cap etc are cleaned up real good.

JRSutton · Jul 8, 2011

haven't done much work on these myself, so can't help much - but if you rotate the engine by hand, can you hear a strong click when 1/4 should be firing? (tdc on 1/4)

If so, it generally means you should take a closer look at the points, clean them up, see if there's anything going wrong there.

If it doesn't click, you might have bigger problems.

rustred · Jul 8, 2011

you check the firing order? oh, i see you say their not firing. you check the rotor, and cap for cracks? seams like someone switched the wires to me.

gene bender · Jul 8, 2011

Do you have the wires going to the plugs in the correct firing order

teddy52food · Jul 8, 2011

Switch 1&4 wires in the cap & try it.

Janicholson · Jul 8, 2011

The firing order on the engine is correct, 1342,
However the cylinders are numbered from front to back. If you look at the cap from the rear, the wires go CW:
2-1
4-3
Best of luck. Jim

F-Dean · Jul 8, 2011

Check to make sure that you have the firing order going in the correct direction (clock wise vs counter-clock wise).

Tom Fleming · Jul 9, 2011

Replace the points, condenser, and wires. Make sure the wires are copper core, and not resistor wires. If what you are saying is correct, I would highly doubt it would be the coil, since it produces spark on 2 of the wires.

I bought a tractor that behaved in a similar fashion. 2 wires were copper and 2 were graphite resistor. replaced all 4 with new copper core, and what a huge difference.

rustyacresnd · Jul 9, 2011

I wouldn't think that points/condensor etc. would make hit on 2 and miss on the other 2. Possibly a cracked dist. cap if it ran ok last time it was used and nothing has been changed like 2 plug wires being switched.

Owen Aaland · Jul 9, 2011

(quoted from post at 17:26:00 07/09/11) I wouldn't think that points/condensor etc. would make hit on 2 and miss on the other 2. Possibly a cracked dist. cap if it ran ok last time it was used and nothing has been changed like 2 plug wires being switched.

You are correct for a distributor since that runs at 1/2 engine speed so the points ride on a came with four lobes. The main shaft of the magneto runs at crankshaft speed. Since the cam for the points are on the main shaft there are only two lobes in the magneto. Each lobe breaks the points for evfery other cylinder. Not likely to be the problem but it could cause the scenario described.

rustyacresnd · Jul 9, 2011

ok.....missed the part about the mag!

Farmall A missing on 1 4

chad from michigan

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Tyler Jackson

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Tyler Jackson

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JRSutton

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rustred

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gene bender

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teddy52food

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Janicholson

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Tom Fleming

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