it should only be tickin over at about 1000rpm, no more unless the choke is on, sounds like the jets and adjusting screws are all out of sync, if carb is not set right all sorts of problems can come, hence why the industry went on to fuel injection, easier to determine where/which bit is set wrong. The throttle valve in the carb along with the jets is set to the engine, alot of people get off the peirberg onto a weber due to these problems, the main one was the auto choke, even played up after a manual conversion, like the carb was looking for the extra fuel etc...
Flat spots on a carb system can come from bad vaccum system ie leaking, miss configured or non functional, check the diaphram on the side of the disi, take the pipe off whilst running engine and put finger diaphram exit pipe and move the throttle you should feel a suck on your finger, check the pipe into the rear of the clocks too, i'm sure you'll get it sorted, its a dub!
