Reply To: Monro tiller spark plug

[charlie]

“That’s the point I’m getting a great spark to earth without the plug attached but nothing when the plug is attached”
With the plug out of the engine and firmly clamped to and making a good earth contact with the engine you should get a spark with the plug lead connected. If not there is a problem with the plug, what is the plug gap it should be 0.025″
You will not get a spark across the plug gap if the metal body of the plug is not adequately earthed.