theory of ignition - troubleshooting

[HalcyonS]

Hi all,

last week I had a new 'won't start' issue, after a season of good starts. It took maybe 20 tries before it started up, lumpy at first, and it spat some black flakes. Yesterday it nearly caught, only once in at least 20 tries. So I have some diagnostic questions. Earlier this season I installed a new battery, changed plugs, overhauled carb, checked fuel lines - facet pump is working well. I've had the dist apart and the advance springs are intact and not seized. So everything points to ignition...

1. I've had stuck valves in the past, though not recently. It would take a lot of stick valves to totally prevent ignition, wouldn't it?

2. If I want to check spark, but my ignition switch is more than an arms reach from the engine bay - do I set up some kind of parallel switch or hot wire in the engine bay?

3. Checking a spark is achieved by pulling plug wire and turning engine over while holding wire 1" from plug?

4. How do plug wires fail? Can you test with a multimeter?

5. How do points and condenser fail? How often should they be replaced?

6. I started thinking about the coil - transformers only work with AC.
How does the coil make AC or where does it get it from?

any tips gladly received
Simon