Mculloch MT300x Strimmer will not stsrt?

Hi,
I have obtained an old, good coniditon2 stroke petrol strimmer.
All parts look functional and in goods condition.
When I unscrew the spark plug and lay it against the strimmer metal body, then pull the starter, this rotates the flywheel, I am not getting any spark. (The run switch is on!) What can I do, can I do any check with a meter?? How can I check to see if the plug lead is O/C??

Bill