I put in a brand new plug after the one in there got wetted, but still not even a hint of starting. How do I tell if the spark might be failing under compression? I once witnessed a rally mechanic working on a Lotus Cortina engine with a misfire hold the plug with one hand and stick a finger from the other hand up the HT cap – ‘that ones firing OK’ was all he said but he was jerking about like the Policeman in Punch and Judy!