Once the steering feel was far improved by lubrication, too sensitive accel feel was appeared up. I have been in the thought that distributor should be equipped both vacuum advancer and centrifugal one and they work well in harmony. Vacuum advancer react more quickly than mechanical centrifugal advancer, so the former one is indispensable to obtain smooth and sensitive accel feel. Consequently, BTDC 5 degree was applied as a common sense. Remembering past, I applied TDC 0 degree on the way back home from Kobe Transport Bureau, acceleration became better. The bad habit to have a tendency to cough and stall if accel pedal was pushed down too much. Consequently, I determined to think it over combustion timing consulting VW manual for '72 Super Beetle manual.
The diaphragm vacuum advancer equipped on 34PICT3 carburetor was so strange as to have double diaphragm, they are for advance and delay construction respectively! Also, dash-pod was set at idle stopper point to prevent sudden low down of rotation. Double diaphragm construction is aimed at keep ATDC 5 degree idle rotation. All of these measures are purposed for Anti Pollution exhaust gas controlling.
Judging from the vacuum control performance appeared in the manual, they always act antagonistically leading to no advance nor delay as a matter of fact.
According to the information from manual description, no vacuum control and centrifugal advance controlling only is done!
Then I close vacuum hose for advance only diaphragm activation with 5mm dia. brass material and the combustion timing was set at zero degree TDC. It means that only centrifugal advancer is alive from TDC 0 degree.
The impression of AD motor I have been in my mind for long time has completely revolved---now no complain at all! Bingo!!
No hesitation to push down accel pedal, no coughing nor stall down. Probably most of my elder brothers might know that 009 distributor has no vacuum advancer, this is why this one is so popular in US. A 10-year mystery has solved!
This description is done under happiest emotional condition.