I had somewhat similar symptoms. I rebuilt the carb, that did not fix the problem. Then I replaced the fuel pump, that did not fix the problem. It ended up being a problem with the points and condensor.
I found videos on youtube that went through the carb rebuild step by step, so you might try searching for videos for your carb.
One tip (for this and just about any project)...take pictures. Take pictures of the carb on the motor from each side. For each linkage that you end up disconnecting, take a picture before disconnecting. The pictures will help when you realize that parts seem to be able to put back on multiple ways (which side is up, which side faces in or out, etc.). That was most helpful to me. The joy of digital cameras (or even just cell phone pictures) is that the pictures are free. You can't take too many.
