Good point. Just last week I had to fix my ignition switch for that very reason -- the RUN contact was all corroded.

Sucker'd crank over just fine, but as soon as I released the key to the RUN position, the engine died. So when I released the key from the START position, I rotated it slowly back towards the RUN position just until the starter disengaged. It ran. I could drive the car as long as I held the key there. Took the switch apart, burnished the contacts, and it's fine now.

Seabee -- when you say you have no spark, do you mean while CRANKING?