Normally only a few things are required to get a motor started; Air, Fuel,
Spark.

Remove all plugs and get help holding them to the block to ground the plugs
using insulated plastic pliers. Ground all plugs before cranking engine.
Have someone turn the key to the start position and verify the presence of
spark at each plug. Obviously if no spark, concentrate on the ignition
system. If you have spark, then put the plugs into the engine, open the
throttle and don't choke the engine. While cranking the engine, spray
starter fluid in each carb. If it starts, remove and clean out the carbs,
including the jets and float needle and seat valve..

With these items present, it's gotta run !

Don Dando