Carb Difficulty
 

Good point Dominik, I never considered the power valve going out. Although from what buzzmobile is describing, now that his mech. advance is freed up, I tend to think his choke butterfly might be hanging a little bit. Until engine is fully warmed up if choke is still on it too will cause an over rich mixture at low RPM. I'm assuming it's heat operated and not an electric choke. I would loosen the screws on the black housing where the bi metalic spring is. Keep in mind the engine is cool or at least room temperature, then I would turn the housing to where the choke butterfly would just barely close. Then I would manually open the choke to full open, crack the throttle open a little bit to see what the choke would do. If it closed (lightly) then I went ahead and tightened up the choke housing screws. If it closed shut tight, then I went back and turned the choke housing to open a little more. This was a trial by error process but I never had any problems with the automatic choke. The choke came on when the engine was cold but as it gradually warmed up the bi metalic spring relaxed allowing the choke butterfly to open up right away. So buzzmobile the next thing I'd look into is your choke and see what it's doing. If it operates OK then yes I'd think about replacing the power valve. Double check your fuel level make sure it is at bottom of sight plug hole on side of fuel bowl also.**)

have no choke butterfly hooked up....mechanical butterfly but not hooked up to a cable and always open

Carb Difficulty
 

OK since you posted it settles down after warming up. Basically nothing is wrong. With no choke engaged at all a cold engine needs a slightly richer mix of fuel to air ratio to run smoothly. It will pop and fart until thermostat opens up at which point with engine approaching normal temp. operation, engine will settle down and run smoothly unless you have a wild cam grind. The rule of thumb is this, if an engine runs erratically it is usually a mechanical or a fuel problem. If it is a steady miss almost at any RPM then it is usually an electrical problem. Since you don't have a choke the engine will run rough until it warms up. So since you cleaned up the mech. weights in the distributor I'd say you're OK. Oh yeah. One more question. Does the engine pull OK when you hit the throttle with no miss in it? If it does then you're allright. :MECOOL: