Hello,

I recently bought a 1972 250 with the dual Zenith carbs. It runs ok, but it has severe hesitation and cold starting problems. It idles pretty rough, and when I step on the accelerator, it either stalls or hesitates. If you ease into it, it willingly climbs into the high RPMs and sounds/runs ok. Anyway, its got me stumped...I've cleaned the carbs, replaced the distributor, wires, plugs, air filter, alternator, fuel filter, cleaned the gas tank...and it still runs pretty much the same! I tried adjusting the timing yesterday, but that didn't seem to help at all. What else should I look into? Is there a fuel filter screen anywhere in the fuel system? I've only replaced the filter. Could it be a weak fuel pump? Or maybe I need to adjust the distributor?
If anyone has any ideas, I'd really appreciate it. This is my 1st MB, so I'm a little unfamiliar under the hood.

Thanks!