Took it apart again and cleaned the fuel tank, not a speck of anything on it. Cleaned the fuel filter although it looked pretty clean anyway. Cleaned the fuel line and then took the carby apart, found some rust sediment, gave it a good clean with carb cleaner, then air compressor through it all. Put it all back together and slightly better performance ie it ran for a little longer but always with that sort of irregular rhythm like it's missing. Checked the spark, to me it seems like it's not regular ie not a constant spark. Still getting a loud audible blue spark though. I'm now focussing on the condenser and looking for a second-hand one to try out. I do have an automotive multimeter that will measure capacitance but I don't think I can use it to check my current condenser, anyway on we go ...
