Will Fite but not through a plug

[woden_88]

I loaned my mower to a guy and he brought it back not running so I checked the plug and replaced it 3 time with new ones pulled the cover off cleaned the flywheel and coil of rust put it back together and saw it would fire at the wire if I held it but can someone please tell me why it will not fire threw the plug? Thank you

 

[ILENGINE]

Either a partially grounded kill wire, or a bad ignition module. Remove the kill wire from the module and see if will fire then. If not replace the igntion module.

 

[chance123]

When you check for spark on the plug, is the body of the plug touching a good ground?