4 Jaw Chuck:
You seem to know quite a bit about vacuum advance mechanisms. Here's a (likely painfully easy) question:
Should I be able to detect a broken vacuum advance can (diaphram...whatever) by sucking on the hose?
Some people have said I should be able to, others have said I shouldn't. I tried it out on my car, and I got no suction at all (i.e., I sucked until I was purple in the face!)