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[Phil (PJ) Berks]

This follows on from the carb problem last month which has not yet been resolved. I seem to have a weak spark which has developed over the last month or two and may be the problem with the rough running which I put down to the carb. I have installed new points and condenser and set the timing. The plug is new and the mixture is very rich/sooty, it wasn’t and I haven’t changed anything on the carb – still standard. The spark is white in colour but the engine starts readily enough and ticks over when up to temperature, however under load it misses and jumps about.......The battery is showing 12.5 v with no load and drawing .25A with the ignition on. With the points closed it is drawing just over 3A and the coil starts to warm up – engine not running. With the engine running it still draws 3A but the battery lead is warm to the touch as is the coil. The coil resistances all seem to be within working parameters. My view is I need a new coil, however before going to that expense HAVE I MISSED SOMETHING? Many thanks Phil(PJ)

[PeteF]

The plug shouldn't be very sooty, at least the electrode shouldn't be, so it could be just running too rich. You didn't get one of these fake ngk plugs that are kicking around did you?

[Phil (PJ) Berks]

Pete, That was a good thought and a very informative thread so I have checked all my plugs and they seem to be legit. The annoying thing is I haven’t touched the carb settings from when it was running weak. The plug lead and cap are new, perhaps the timing is too retarded, however the spark at the plug is week. I will check the “kill switch” for high resistance as I once had a CX500 that refused to start and found the kill switch had a resistance of 7 ohms when in the on position which killed the CDI unit......Phil(PJ)

[PeteF]

Float height? It shouldn't have altered unless the float's leaking but.....