No Spark

[rdmytro]

I have a 8N with side mount distributor and a 12 volt system. Yesterday, I was using my tractor to cut a field. It ran fine for 3-4 fours, and then it just stopped. I checked to see if I had a spark, and no spark. I bypassed the ignition switch, still no spark. I changed the coil. I cranked the engine and got a spark for a few turns, then no spark again. I checked the wiring for a short and found a short in the screw insulation on the distributor. I replaced the rubber washer, and the short was fixed. I replaced the coil again, the condenser, and points. I cranked the tractor and got a few sparks then nothing. I can"t find any other shorts. What could cause the spark to stop after a few cranks?

 

[Dunk]

(quoted from post at 22:05:15 05/24/09) I have a 8N with side mount distributor and a 12 volt system. Yesterday, I was using my tractor to cut a field. It ran fine for 3-4 fours, and then it just stopped. I checked to see if I had a spark, and no spark. I bypassed the ignition switch, still no spark. I changed the coil. I cranked the engine and got a spark for a few turns, then no spark again. I checked the wiring for a short and found a short in the screw insulation on the distributor. I replaced the rubber washer, and the short was fixed. I replaced the coil again, the condenser, and points. I cranked the tractor and got a few sparks then nothing. I can"t find any other shorts. What could cause the spark to stop after a few cranks?

Check the wire where it enters the distributor.

 

[Bruce (VA)]

Get your meter out & follow the volts. Start at the points & work backwards. Key on, points open, measure the voltage across the points. Should be battery voltage. Go from there to the side of the distributor, then to the coil. Chances are very good that when you wiggle that wire going into the distributor that it will get voltage to the points.....or lose it as Dunk said. That is a very common failure point on sidemounts & often hard to find because it is usually an intermittent short. (If you find the short there, the Master Parts catalog lists everything you need on page 154. You can make the strip and you could also make the insulators as well. But, somethings are just easier & in the long run cheaper to buy. Get the strip, 12209, screw 350032-S, 12233 bushing & 12234 insulator & just replace it all.)
50 Tips

 

[G6 at Snook, TX]

One other option you might try for stop gap purposes is to run a light gauged wire, 14 or 16, from the coil through the distributor to the condenser and points connection. It is easy to do, but the fit is tight. If you do this, make sure the weights don't catch the wire. If you are patient and don't need it right away, I suggest you order the parts Bruce laid out for you.

 

[rdmytro]

I ran a wire directly to the points. Still no spark. When the wire shorts does that cause the coil to fail, and need to be replaced? The coil was warm to the touch when a I removed it.

 

[Bruce (VA)]

Your coil is fine. The problem is upstream.

Follow these directions, step by step, just as it's written here & you will get the tractor running.

Remove the distributor cap & make sure the points are open.

Turn the key on.

Check the voltage across the points. It should be about 12.35v if your battery is fully charged.

Next, check the voltage from the coil to the points on the little wire going into the distributor. (that's the primary wire)

Next, on the other side of the coil is another small wire; that's the wire from the ignition switch. Check the voltage there.

That is what I meant by "follow the volts" in my previous post. The volts start at the battery & go to the open points. When the volts stop, that's where the problem is.

Post back w/ the results.
50 Tips

 

[rdmytro]

The voltage at all of the locations battery, ignition, coil +, coil-, and points is 12.14.

I noticed that the rotor wasn't seated on the shaft. I removed the rotor and noticed that the rotor flat spot was worn. I reinstalled the rotor and distributor cap, and cranked the engine. I removed the distributor, and it seamed the rotor didn't move. I replaced the rotor, and cranked the engine. And the new rotor cracked in half.


Then, I checked the distributor shaft to see if it had any play. It didn't have any movement.

Before I replace the rotor and distributor cap, could anything else be causing rotors to wear and crack?