RE: Stihl 4-mix 65cc questions
I have not. I have several new carbs coming. I also have a new ignition coming. I suspect my current test stand ignition is not advancing properly.
I doubt a spring on the carb diaphragm is needed. The pulse is from the crankcase and is the same as a 2-stroke, positive and negative pressure. There is a passage way from the crankcase to the intake manifold. The pulse is probably not as strong as a regular 2-stroke due to the crankcase charge being free to go in and out of the carb.
There is plenty of experimentation to do.