Hi

Mine (with a carby) has compression down on cylinder 3 causing slightly erratic idle and occasional stalling (compression is erratic, but averages about 20% lower than the others - it's got to be a burned valve, probably rotating to expose the bad bit from time to time). Over the last 2 weeks or so, it started getting worse and worse - wouldn't idle less than 1600 rpm etc. I'd replaced just about everything recently in the plugs/points/plug leads/condensor etc area. In desperation, I put in another coil and lead from coil to distributor (got them from a wreck) and it's running well again. Testing the old coil (only 3 years old), showed it was way off the specs in the Haines manual. Also, the 3 month old lead had a break in it, right near the coil end - you could see the inner wire didn't make it to the metal clip on the end. I was about to do a head job tomorrow, but I'll go to work instead.

Alan