Over the last few days I have taken the plunge to rebuild the Weber DCD on Marvin. Having removed the carb and stripped it down completely. I noted all the jet and tube sizes and left them all to soak over night in Meths.
I have a spare DCD and between the two of them I decided to rebuilt one carb from the best of both. The choke sizes on the spare are smaller than the old one. The old carb was Primary choke 24mm and secondary choke 26mm. The spare carb turned out to me Primary 23mm and secondary 24mm, I decided that building the carb using this smaller choke tubed body would be better.
Having reseated everything on new gaskets and seals, I turned the key and within a few seconds Marvin was back up running, and smoother than before, the tick over is almost perfectly smooth (a big valve head doesn’t help tick over) I am guessing the increased air speed in the carb has helped things.
I noted black smoke from the exhaust and leaned off the idle mixture a bit and rest the tick over speed to compensate, all sounded good. A quick couple of miles test drive told me several things, he is far more road mannered and drives smoother in low speeds. Tomorrow I shall go for a longer drive.
Having pulled 6000rpm in 3rd gear then up shifted I noted the car backfire and it was lumpier above 5500rpm, This leads me to think the mixture is now too lean. But all this is part of tomorrows plans.