[Phillyfanfrombirth]

Usually if it just "stops", it is either gas or spark...

If you are getting spark, that means that your timing chain is in tact. I've seen a cam break before... the engine will crank very quickly if that is the case, and you won't get compression out of all of the cylinders.

Now, what you didn't answer...

Engine size?

You say it doesn't "fire", I'd assume that means that it cranks alright though?

Was it running, and just suddenly shut off? Or did it run the last time you tried it, but won't run now?
How's the choke look?