ohiojim

Well-known Member
Rebuilt a Farmall super m, the front cylinder is missing, I can pull the plug wire and hold it about an 1/8 inch from the plug and it runs fine, I regaped the plug, swapped holes with a running plug and it's the same, new distributor cap new wires...I use to know what that ment but old age crept in,..any ideas..
 
Been there, done that. Changed wire, cleaned all connections, I remember back in the day they had a special wire with the built in gap for this problem, but I don't remember what caused the problem...
 
It usually means a sooted up partially fouled plug. If the plugs are running dark, it may be too rich or the plugs are too cold, especially if it doesn't get worked hard.

It can also be weak spark. Did you replace the points and check the gap? Closed up points can do that.

How is the spark at the plug end of the wire? Should give a 1/4 inch minimum hot spark to ground. Check the spark at the coil also, should get 1/2 inch to ground easy, even more. Could be a weak coil or the wrong coil or coil/resistor combo if it is a 12v system.
 
I agree with Steve, sounds like a plug is fouling out. If its running too rich the plug can have a flat black even sooty look or if she's burning oil more of a shiny black color. A nice warm gray is the color to have. So often its bad points that cause a weak spark, make sure they are clean and gapped correctly. A crack or moisture in the dist cap can also cause problems, check that also and insure the wires arent leaking HV to ground while you're at it.

John T
 
I do not know if this can be your problem but just by a chance did you check to see if the distributor shaft is reasonably tight in the bushing? I am not sure if a vacuum leak could be your issue or not. With the shared intake port it would seem odd it would be only cylinder 1. Maybe if the leak is at the front side of the port it may lean out number 1 more. I am not sure, does a lean mixture take more spark to fire? If it was something with a valve , like lash set wrong you would think that it would not clear up with the gapped spark.
 
I would check that the points are opening the same for each cylinder. Maybe the lobe for that cylinder is worn. Also check compression for that cylinder and compare it to the others. It should be close to the other cylinders.
Dave
 

cvphoto125488.jpg
look up Astro-Jet pulse amplifier. Just a spark gap. Got mine at a tractor show 20 years ago for $20. Had the same demo set up; V-8 with fouled plugs.
 
for 5 minutes work and a few inches of baling wire I made them just wrap around the porcelain and run by the end of the plug make a loop for the wire and go.
 

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