There are 3 screws with springs between them and the carb, on the throttle cable side of the carb. A "T" screw, a flat head screw next to it and the big phillips head screw under them.
Turn the phillips head screw in all the way and leave it there.
Set the "T" screw, this is your Top/High end adjustment. Turn it all the way in until you feel it stop. Turn it back out 1 and 1/4 turn.
The screw next to it is your low end screw. Turn this one all the way in, back it out 1 and 1/4.
Start your goped, let it warm up. If the Idle is TOO HIGH, turn the low end screw OUT 1/16 of a turn at a time until it idles very low but doesn’t die. If the idle is too low and it doesn’t stay running, turn it IN 1/16 of a turn at a time until it stays running.
Ride your goped. If the motor sputters and makes a gurgling sound, turn the t screw in 1/16 of a turn at time.
If your goped goes fast but the motor cuts out at high rpm and runs erratically, turn the t screw out 1/16 until it runs good.
Improper oil mixtures, improper tuning or riding at full throttle for long periods of time.