Weak Spark causes??: Yamaha ox66 225hp

My mech is troubleshooting why my engine starts hard....have gone thru all the usal suspects....

He said that the only thing wrong is weak spark...but needs to evaluate...

I have new batteries, good plug wires - resistance fine, new plugs, gapped properly, cleaned up all ground plug wire connections....

what are the elements that create a good spark between the battery and the plug...

thanks.

[boats.net]

Best to test all ignition componets, could be stator, CDI, ignition coils or possible pulsor coils.