"Assuming it has decent compre
"Assuming it has decent compression, the only other thing it needs is gas and air mixture, along with spark at the right time.
You can pull the high voltage wire from the coil to the distributor, and see if you have a nice fat spark to the nearest frame point while cranking. This will tell you about spark.
NOTE: Don't do this if there is spilled gas or gas vapors in the immediate area. Keep an extinguisher handy.
If the spark checks out, then remove the flame arrestor and look for a squirt of gas down the primary carb barrels when an assistant gives her some throttle. (Engine off!) You should also smell gas strongly.
If there is no evidence of fuel, the carb bowl is empty, and you likely have a plugged fuel filter (main or at the carb inlet), or a bad fuel pump.
If it is equipped with an electric fuel pump, this pump will not run except in the "start" position, due to a safety oil pressure switch, that is designed to stop the fuel pump (and hence the engine) in the event of low oil pressure. This seems to make the 4.3 very hard to start after a long layup. Many on this site have had similar troubles, myself included.
You can remove the fuel line at the carb, run some hose to a bucket, and hot wire the fuel pump to see if it works and pumps gas. Again, beware of the extreme fire hazard doing this.
Hope this helps,
Rod"