Originally Posted by shakran

if an engine cranks but won't start, you either aren't getting fuel, or you aren't getting spark.

First, remove a sparkplug, hook it up to the plugwire again, and crank. If you don't see a spark, remove the plug wire and hold it against a metal bolt on the engine while cranking. Look for the spark. If you don't see it, you have an electrical problem. Start with the distributor, coil, and ignitor. If you do see a spark, but didn't when you had it hooked up to the plug, replace the plug, and make sure it's gapped properly for your engine.

Assuming you have spark, take off a fuel line and crank the engine (obviously do not smoke, or have any open flame or hot items in the area when you do this, and do it outside so you don't burn down the garage.) If you don't see fuel spurting out, then you have a fuel delivery issue. Probably either the filter is clogged, or the pump is bad. Take off the fuel line before the filter to see if fuel is getting that far. Keep working backwards until you get to the pump to find the source of your fuel stoppage.

Another possibility is that the timing is radically off, which would mean the spark is happening, but not when the fuel/air mixture is right for combustion. Try adjusting the timing backwards and forwards while cranking to see if you can get it started, and if you can, then time the engine properly with a timing light (available cheap at auto parts stores, and I believe NAPA and Advanced Auto will lend one to you.)