[trevarthan]

We removed the distributor cap this morning and discovered the screws from the coil were poking through the cap and there was some minor arcing trails to the screws, so we returned the cap for the third time and this time I bought a higher quality coil from OReilly. I bought the duralast gold cap from Autozone (also higher quality, but still Autozone brand).

The higher quality coil from OReilly came with shorter screws. I think that was the problem with the Autozone cheapo coil. The screws were too long.

After installing all of that, it still was missing and stuttering when revving it and under load.

At this point I repeated the mixture tuning procedure (using a vacuum gauge on the manifold vacuum port), but with the engine cold and with the air cleaner installed. The first time I did the procedure with the engine warm and the air cleaner removed.

I found the perfect mixture setting was leaner this time.

We revved it and the miss or stutter was gone. We drove it and it was still there under load, but greatly reduced.

So I leaned it another quarter turn. It improved again.

Another quarter turn and it was almost perfect.

My theory is that the platinum plugs we installed with smaller gaps have a shorter spark so they have a little trouble igniting the fuel. I'm probably going to install regular non-platinum plugs and gap them larger and see if that allows me to run closer to the ideal mixture with the air cleaner on.

Anyway, it's running! Not stalling. Power is good. Maybe just a hint of hesitation.

Yes, we rebuilt the carb. However, I think the original problem was a bad coil. We replaced it numerous times, but it was never quite right and I think we damaged it the first couple of times by leaving the ignition on after a stall, in ignorance.