Spark Test
NOTE:
When ignition coil is triggered, spark is supplied to 2 spark plugs at one time. One spark plug fires during compression stroke and the other plug fires during exhaust stroke (waste spark).
Check for a strong Blue spark at coil wire and at each spark plug wire by holding wire terminal 5/16" from ground while cranking engine. Disconnect and inspect all related ignition system connectors and harness. Clean or repair as necessary.