If your carb has a SCREW near the AIR FILTER side of the Carb it has a AIR RATIO MIXTURE Adjustment screw.
Turning the Air Ratio Mixture Clockwise RICHENS it Turning it Counter Clockwise LEANS it.
The Idle Speed screw is in the Center of the Carb. Turning that Clockwise RAISES the Idle and Turning it Counter Clockwise LOWERS the Idle.
[RED]IF YOUR CARB HAS A SCREW ON THE INTAKE SIDE GO SEE 4TS CARB TUNING.[/RED]
[blue]ADJUSTING YOUR AIR RATIO MIXTURE:[/blue]
[red]YOU WANT THE HIGHEST RPMS OUT OF THE AIR RATIO MIXTURE SCREW:[/red]
Start your scoot and Get The Engine Nice and Hot about 5 minutes so that the Enricher IF it has one is no longer Allowing Extra Fuel to come in. Then do the following to fine tune the Air Ratio Mixture:
NOTE: The Air Ratio Mixture is very [red]SENSITIVE[/red] and it does not take much to be off so only make small adjustments.
[red]AIR RATIO SCREW:[/red]
FIRST TRY RICHENNG THE AIR MIXTURE FROM ITS CURRENT SETTING:
[blue]RICHEN THE AIR RATIO MIXTURE:[/blue]
1. Turn the Air Mixture Screw CLOCKWISE 1/8 of a turn and wait 10-15 seconds to let the engine catch up with the new setting.
a. If the RPMS go up REPEAT #1 UNTIL the RPMS GO DOWN OR NO CHANGE(then go to b).
b. TURN the Air Ratio Mixture Screw COUNTER CLOCKWISE 1/16 and that should be your highest Air Ratio Mixture setting—GO TO #3.
[green]******[/green]If on the FIRST 1/8 TURN from the STARTING Position IN #1 ABOVE the RPMS GO DOWN OR NO CHANGE , turn the Air Ratio Mixture Screw Back the 1/8 turn to the Starting position and wait 10-15 seconds until the engine catches up -- GO TO #2 [green]******[/green]
[blue]LEAN THE AIR RATIO MIXTURE:[/blue]
2. Turn the Air Mixture Screw COUNTER CLOCKWISE 1/8 of a turn and wait 10-15 seconds to let the engine catch up with the new setting.
a. If the RPMS go up REPEAT #2 UNTIL the RPMS GO DOWN OR NO CHANGE(then go to b).
b. TURN the Air Ratio Mixture Screw CLOCKWISE 1/16 and that should be your highest Air Ratio Mixture setting—GO TO #3.
[red]IF YOU GOT TO THIS POINT AND NOT INSTRUCTED TO GO TO #3 THAT MEANS THERE WAS NO CHANGE IN RPMS FROM DOING #1 or #2 ABOVE, IT IS TIME TO CLEAN THE CARB:
YOU NEED TO CLEAN YOUR PILOT JET AND PASSAGE AND AIR PASSAGES AND THEN START FROM #1 AGAIN.[/red]
[blue]IDLE SPEED SCREW:[/blue]
The Idle Speed Screw on a Carb that are on most 2Ts is in the CENTER OF THE CARB LEFT of the AIR RATIO SCREW.
To Lower the IDLE you turn it COUNTER CLOCKWISE to Raise the IDLE you turn it CLOCKWISE.
3. If after adjusting your Air Ratio Mixture your idle is to fast Turn the IDLE SPEED SCREW COUNTER CLOCKWISE until the Rear Wheel JUST Barely wants to Turn ---GO TO #4.
[red]TEST YOUR ADJUSTMENTS:[/red]
4. Now give the Throttle a QUICK twist and the RPMS should climb up quickly without hesitation or bogging and come down to where you set your Idle at.
[blue]Problems with the IDLE:[/blue]
1. Give the throttle a quick twist:
A. If the rpms drop below idle speed, then recovers (or stalls), it is [red]RICH[/red] —Turn the Air Mixture Screw Counter Clockwise 1/8 turns at a time and go to #1.
B. If the rpms do not drop quickly to the idle speed but hang and drop slowly it is[red]LEAN[/red] —Turn the Air Mixture Screw Clockwise 1/8 turns at a time and go to #1.
100% agree. Also after your IT folks add a product to your page...have a Tech verify the info..have seen several sites with incorrect info...i.e. one lists QMB139 roller weights as 18X14 and 9-17 gram. So I called them..and they guy said.."That is what they are for that engine".... D8
Please find and post that link to the research where they explain that mixing oil will improve engine life. Ask the Mods to put it in the Tech section so we can refer folks to it. They have put a few things there from me and many others. The more we share what we learn...the better the riding experience for others...and less breakdowns which can frustrate Chinese Scoot owners. Thanks in advance for the link to the research. Interested in reading it...as it is THE very pumping and circulating blood...that keeps our Scoots alive. 
% of our night vision. That is why we cannot see color at night. I could go on..but I am wasting my College Degree and what I learned in a Human Physics class on someones speculation...assumption and continual off the wall ramblings. Here is a pic for ya...now show me yours? High School Diploma even. Wanna impress me WITHOUT using Wikipedia..tell me the frequency for each of the Primary Colors and what the human frequency threshold for light is. 
