Uneven fueling on Weber 45 dcoe

[Mk1Tom]

Hi folks, I've recently completed the build of a classic mini with the intention of hill climbing it.

The engine is proving difficult to set up however as first I had an issue with the megajolt mapable ignition and now after trying to road test it, it is running like an absolute dog.

It runs rough and at some points lets out almighty backfires, when accelerating at some points it is almost like someone has turned everything off and power just drops as though I have taken my foot off the pedal.

We whipped the plugs out and 3/4 are running very rich and 1/2 are running ok.

Does anyone know of any reason my weber would be fueling unevenly? Its just been jetted etc by a man who knows what he is doing so I think there may be a problem with the carb somehow.

Is there anything I can do to clean it all out?

I'm getting fed up of this bloody car

Many thanks