I've got some strange ignition symptoms now, which might be causing or masking the other problems. New plugs fitted for this test btw, which happen to be DR7ES rather than DR8ES, as that's all I had.
I've tried checking the ignition timing with a strobe light today, and get some strange readings. It's the sort of light that you clip onto the plug lead, not in-line with the lead, I'm going to borrow one of those next - read on...
Cylinders 3 and 4 hardly give a strobe at all - the flashes are very intermittent and random (like a few seconds with no pulse, then a few randomly, then none, one or two more, a few more, long time without any etc).
Cylinder 1 gives a good steady strobe, but the timing is showing fully advanced when at tickover.
Cylinder 2 gives a good steady strobe, and the timing is spot on correct (which is amusing as this is the only cylinder I thought I had problems with) but from a timing perspective it's the only one that works properly!
Does this suggest wiring or coil or CDI problems? Bit confused by the fact that it's not got a problem in "pairs" like 1 & 4, which would point to a coil or CDI.
still planning to strip the carbs as I'm sure there is fuel problem on number 2, but it's odd that number 2 is the only one with timing that's anywhere near good.
I'm going to get some new DR8ES plugs, and change leads - any recommendations?
Phil