Found this thread while searching for a long standing problem with my Super 8 150cc.
In the morning, the scooter starts up fine, but the first 5 minutes of ride the engine goes near to stall each time I decelerate and accelerate. Unfortunately this happens in turns and stop lights. Even when accelerating from idle (i.e. green light), there is a moment rpms go down instead of up, the engine may even stop completely, but if it doesn't stop, the rpm go up and I can ick up speed. I have noticed this is related to temperature, in colder days is way more obvious, in hot days may not even notice it (had the scooter from nine months, bought it used, and has currently 2200 miles in it).
Searched the web for months, and read all sorts of ideas (the air filter, the dirty carb, the diaphragm, the spark plug, the idle level etc). Changed oil and spark plug, still the same. Used Seafoam for some time (also to winterize the scooter), still the same. Two mechanics told me the carburetor must be dirty ($150 to cleaning it). Already paid $70 to someone to clean it, but I doubt he cleaned anything, he showed me dirty ear cotton buds, and I don't think you can clean a carb properly with those. \The good mechanic thinks he is a doctor, has a $60/hour rate and meets only by appointment, plus it's too far from my home... plus the scooter is running ok beside this morning issue.
Now, the symptoms make me think this has nothing to do with the dirty carburetor, why would the fuel mist in the dirty carburetor depend on temperature? Actually sounds like a choke problem to me. I see already two people found the auto choke installed wrong.
My question is, did you guys have problems in the morning while the autochoke was installed with reverse polarity?
If anyone has something to suggest, I'd be happy to hear. I have ridden the scooter even at 35 degrees F, everything works ok once it worms up. Max speed 62mph.