Classic/Antique Car Repair: tractor, old motorcycles, paint thickness

Question
i have an old tractor, i am not getting any spark at the plugs,the points are firing,can you help.

Answer
I'm a bit out of my field here, but since you have points, I assume you have a normal Kettering ignition system, not a magneto.  If that is the case, and you see spark jumping at the points, there are only a few possibilities to examine to track down lack of spark at the plugs.

If, on the other hand, you have a magneto system, I'm totally useless - I just don't know much about them.  You can try some of he following tricks to diagnose it, but beyond that, you're going to have to ask a small engine specialist (like old motorcycles or something else that used magnetos).

First, unscrew one of the spark plugs and lay it on the block or head casting so the outer shell is within a paint thickness of touching engine ground, with the high voltage wire connected.  Then spin the engine with the starter to see if you can see a spark jump across from the center terminal of the spark plug to the outer shell.   If you see that spark, note the color of it.  Pull the wire off the plug end and support it about 1/4 inch away from the block.  If you also see a spark jump there when you crank the engine, the ignition system is OK - there's some other problem.

If you don't see the spark jump, or if it is so weak that it can't jump 1/4 inch, you may have a bad condensor, or you may have a bad coil or a dirty cap on the coil, or your plug wires may be bad.  Start out by cleaning the inside and outside of the distributor cap, the coil "tower" (where the high voltage wire comes out) and the plug wires.  Inspect the distributor cap, rotor and coil tower for "carbon tracking" - this will be a fine line across the plastic that comes from a spark jumping where it shouldn't.  It helps to look carefully at the cap, coil, and plug wires at night, with all the lights off - often you can see where the errant spark is jumping from the blue flash.   

If you don't find any improvement after doing all that, try another coil, and replace that condensor.

Let me know what you find out, please?

Dick