transman05

Thanks for the thoughts. The funny thing is, even running for a short time with the choke partially closed, the plugs really soot up. That tells me its getting more fuel than it can burn properly. And these $275-300 carbs aren't a common inventory part.

Its the way some engines react when timing is advanced too far. And if valves were out of time the engine wouldnt run. It runs pretty good with the "rich" condition it has with choke partially closed.

So, this unit comes in for hard to start, wont idle, and have to throttle and choke it to keep it running. Of course higher RPMs make shifting into gear awful. It has the FD620D engine, 808 hrs, ranch vehicle but not abused. I rebuilt the carb, (the right way with dip soak and all the brass), replaced plugs, fuel filter, checked fuel flow from pump, dumped tank and put in fresh gas. It runs some better, but still wont idle or midrange without 1/2-3/4 choke. Very lean, but flowing good amount of fuel through main jets. I've checked for vacuum leak(s), and none found. I have checked coils for proper resistance and found slightly above spec readings across primary terminals but secondary ok. My query is, can the igniter box go out of "calibration" and change the timing on the coils and cause an advanced condition? The engine does "kick" once in a while when starting it. This could also cause the engine to seem to run lean. Any suggestions are greatly appreciated. I prefer that it be the "box" to change rather than the space-locked rear coil! What the hell were they thinking?! Thanks in advance . Dan