Thanks for your comments and advice, guys. Have since found out problem is nothing to with over-fuelling. Believe it or not there is no spark at No1 plug. We have tried changing plug, changing lead, points, condenser even swapping leads around....with no change to problem. she runs reasonably well on 3 but a bit lumpy. I have spoken to all of my close friends who all have classics from Mk's II and III Zephyrs, Zodiacs, Consuls and Caddis. None of them can explain or find what is causing this to happen. Strangest thing happened this afternoon. When we got back from a Classic Rally in Lowestoft, my son and I thought we would have another look at the problem. A friend lent me some LED plugs to check the spark on my plugs. We put all 4 on, started the car, all 4 plugs were sparking! Took the LED's off and started her again. Took the No1 lead off, no change in engine sound or power. Still no spark on the lead. Nothing wrong with lead as we tried it on another plug. I thought I would check the timing. So connected the leads to the battery and to No1 plug. Started the car and the strobe light was working! If there was no power going through the lead why was the strobe light working! This really has me buggered and confused. Any clues, please?